Merge branch 'master' of github.com:lifo/docrails

22 files changed, 438 insertions, 225 deletions

diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb
index 911a5155fd..9743b1b4a7 100644
--- a/activerecord/lib/active_record/association_preload.rb
+++ b/activerecord/lib/active_record/association_preload.rb
@@ -193,13 +193,17 @@ module ActiveRecord
         conditions = "t0.#{reflection.primary_key_name} #{in_or_equals_for_ids(ids)}"
         conditions << append_conditions(reflection, preload_options)
 
-        associated_records = reflection.klass.unscoped.where([conditions, ids]).
+        associated_records_proxy = reflection.klass.unscoped.
             includes(options[:include]).
             joins("INNER JOIN #{connection.quote_table_name options[:join_table]} t0 ON #{reflection.klass.quoted_table_name}.#{reflection.klass.primary_key} = t0.#{reflection.association_foreign_key}").
             select("#{options[:select] || table_name+'.*'}, t0.#{reflection.primary_key_name} as the_parent_record_id").
-            order(options[:order]).to_a
+            order(options[:order])
 
-        set_association_collection_records(id_to_record_map, reflection.name, associated_records, 'the_parent_record_id')
+        all_associated_records = associated_records(ids) do |some_ids|
+          associated_records_proxy.where([conditions, ids]).to_a
+        end
+
+        set_association_collection_records(id_to_record_map, reflection.name, all_associated_records, 'the_parent_record_id')
       end
 
       def preload_has_one_association(records, reflection, preload_options={})
@@ -358,13 +362,14 @@ module ActiveRecord
         find_options = {
           :select => preload_options[:select] || options[:select] || Arel::SqlLiteral.new("#{table_name}.*"),
           :include => preload_options[:include] || options[:include],
-          :conditions => [conditions, ids],
           :joins => options[:joins],
           :group => preload_options[:group] || options[:group],
           :order => preload_options[:order] || options[:order]
         }
 
-        reflection.klass.scoped.apply_finder_options(find_options).to_a
+        associated_records(ids) do |some_ids|
+          reflection.klass.scoped.apply_finder_options(find_options.merge(:conditions => [conditions, some_ids])).to_a
+        end
       end
 
 
@@ -382,6 +387,17 @@ module ActiveRecord
       def in_or_equals_for_ids(ids)
         ids.size > 1 ? "IN (?)" : "= ?"
       end
+
+      # Some databases impose a limit on the number of ids in a list (in Oracle its 1000)
+      # Make several smaller queries if necessary or make one query if the adapter supports it
+      def associated_records(ids)
+        max_ids_in_a_list = connection.ids_in_list_limit || ids.size
+        records = []
+        ids.each_slice(max_ids_in_a_list) do |some_ids|
+          records += yield(some_ids)
+        end
+        records
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 08a4ebfd7e..7da38cd03f 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -4,6 +4,7 @@ require 'active_support/core_ext/module/delegation'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/string/conversions'
 require 'active_support/core_ext/module/remove_method'
+require 'active_support/core_ext/class/attribute'
 
 module ActiveRecord
   class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc:
@@ -1810,12 +1811,12 @@ module ActiveRecord
           callbacks.each do |callback_name|
             full_callback_name = "#{callback_name}_for_#{association_name}"
             defined_callbacks = options[callback_name.to_sym]
-            if options.has_key?(callback_name.to_sym)
-              class_inheritable_reader full_callback_name.to_sym
-              write_inheritable_attribute(full_callback_name.to_sym, [defined_callbacks].flatten)
-            else
-              write_inheritable_attribute(full_callback_name.to_sym, [])
-            end
+
+            full_callback_value = options.has_key?(callback_name.to_sym) ? [defined_callbacks].flatten : []
+
+            # TODO : why do i need method_defined? I think its because of the inheritance chain
+            class_attribute full_callback_name.to_sym unless method_defined?(full_callback_name)
+            self.send("#{full_callback_name}=", full_callback_value)
           end
         end
 
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 5b34ac907c..774103342a 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -182,7 +182,7 @@ module ActiveRecord
           unless options.blank?
             raise ArgumentError, "If finder_sql/counter_sql is used then options cannot be passed"
           end
-          
+
           @reflection.klass.count_by_sql(custom_counter_sql)
         else
 
@@ -332,13 +332,10 @@ module ActiveRecord
       end
 
       def uniq(collection = self)
-        seen = Set.new
-        collection.map do |record|
-          unless seen.include?(record.id)
-            seen << record.id
-            record
-          end
-        end.compact
+        seen = {}
+        collection.find_all do |record|
+          seen[record.id] = true unless seen.key?(record.id)
+        end
       end
 
       # Replace this collection with +other_array+
@@ -375,14 +372,16 @@ module ActiveRecord
         def load_target
           if @owner.persisted? || foreign_key_present
             begin
-              if !loaded?
+              unless loaded?
                 if @target.is_a?(Array) && @target.any?
                   @target = find_target.map do |f|
                     i = @target.index(f)
                     if i
                       @target.delete_at(i).tap do |t|
                         keys = ["id"] + t.changes.keys + (f.attribute_names - t.attribute_names)
-                        t.attributes = f.attributes.except(*keys)
+                        f.attributes.except(*keys).each do |k,v|
+                          t.send("#{k}=", v)
+                        end
                       end
                     else
                       f
@@ -409,11 +408,7 @@ module ActiveRecord
           end
 
           if @target.respond_to?(method) || (!@reflection.klass.respond_to?(method) && Class.respond_to?(method))
-            if block_given?
-              super { |*block_args| yield(*block_args) }
-            else
-              super
-            end
+            super
           elsif @reflection.klass.scopes[method]
             @_named_scopes_cache ||= {}
             @_named_scopes_cache[method] ||= {}
@@ -436,10 +431,10 @@ module ActiveRecord
             # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
             counter_sql = @reflection.options[:finder_sql].sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
           end
-          
+
           interpolate_sql(counter_sql)
         end
-        
+
         def custom_finder_sql
           interpolate_sql(@reflection.options[:finder_sql])
         end
@@ -535,7 +530,7 @@ module ActiveRecord
 
         def callbacks_for(callback_name)
           full_callback_name = "#{callback_name}_for_#{@reflection.name}"
-          @owner.class.read_inheritable_attribute(full_callback_name.to_sym) || []
+          @owner.class.send(full_callback_name.to_sym) || []
         end
 
         def ensure_owner_is_not_new
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index 09bba213ce..7cd04a1ad5 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -211,12 +211,12 @@ module ActiveRecord
             :create => construct_create_scope
           }
         end
-        
+
         # Implemented by subclasses
         def construct_find_scope
           raise NotImplementedError
         end
-        
+
         # Implemented by (some) subclasses
         def construct_create_scope
           {}
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 439880c1fa..c19a33faa8 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -1,3 +1,4 @@
+require 'active_support/core_ext/class/attribute'
 require 'active_support/core_ext/object/blank'
 
 module ActiveRecord
@@ -88,7 +89,7 @@ module ActiveRecord
       end
 
       def clone_with_time_zone_conversion_attribute?(attr, old)
-        old.class.name == "Time" && time_zone_aware_attributes && !skip_time_zone_conversion_for_attributes.include?(attr.to_sym)
+        old.class.name == "Time" && time_zone_aware_attributes && !self.skip_time_zone_conversion_for_attributes.include?(attr.to_sym)
       end
     end
   end
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index d640b26b74..dc2785b6bf 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/class/attribute'
+
 module ActiveRecord
   module AttributeMethods
     module TimeZoneConversion
@@ -7,7 +9,7 @@ module ActiveRecord
         cattr_accessor :time_zone_aware_attributes, :instance_writer => false
         self.time_zone_aware_attributes = false
 
-        class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
+        class_attribute :skip_time_zone_conversion_for_attributes, :instance_writer => false
         self.skip_time_zone_conversion_for_attributes = []
       end
 
@@ -54,7 +56,7 @@ module ActiveRecord
 
         private
           def create_time_zone_conversion_attribute?(name, column)
-            time_zone_aware_attributes && !skip_time_zone_conversion_for_attributes.include?(name.to_sym) && [:datetime, :timestamp].include?(column.type)
+            time_zone_aware_attributes && !self.skip_time_zone_conversion_for_attributes.include?(name.to_sym) && [:datetime, :timestamp].include?(column.type)
           end
       end
     end
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index f588475bbf..aee6f3a7eb 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -7,7 +7,7 @@ require 'active_support/time'
 require 'active_support/core_ext/class/attribute'
 require 'active_support/core_ext/class/attribute_accessors'
 require 'active_support/core_ext/class/delegating_attributes'
-require 'active_support/core_ext/class/inheritable_attributes'
+require 'active_support/core_ext/class/attribute'
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/hash/deep_merge'
 require 'active_support/core_ext/hash/indifferent_access'
@@ -412,7 +412,7 @@ module ActiveRecord #:nodoc:
     self.store_full_sti_class = true
 
     # Stores the default scope for the class
-    class_inheritable_accessor :default_scoping, :instance_writer => false
+    class_attribute :default_scoping, :instance_writer => false
     self.default_scoping = []
 
     # Returns a hash of all the attributes that have been specified for serialization as
@@ -420,6 +420,9 @@ module ActiveRecord #:nodoc:
     class_attribute :serialized_attributes
     self.serialized_attributes = {}
 
+    class_attribute :_attr_readonly, :instance_writer => false
+    self._attr_readonly = []
+
     class << self # Class methods
       delegate :find, :first, :last, :all, :destroy, :destroy_all, :exists?, :delete, :delete_all, :update, :update_all, :to => :scoped
       delegate :find_each, :find_in_batches, :to => :scoped
@@ -504,12 +507,12 @@ module ActiveRecord #:nodoc:
       # Attributes listed as readonly will be used to create a new record but update operations will
       # ignore these fields.
       def attr_readonly(*attributes)
-        write_inheritable_attribute(:attr_readonly, Set.new(attributes.map { |a| a.to_s }) + (readonly_attributes || []))
+        self._attr_readonly = Set.new(attributes.map { |a| a.to_s }) + (self._attr_readonly || [])
       end
 
       # Returns an array of all the attributes that have been specified as readonly.
       def readonly_attributes
-        read_inheritable_attribute(:attr_readonly) || []
+        self._attr_readonly
       end
 
       # If you have an attribute that needs to be saved to the database as an object, and retrieved as the same object,
@@ -724,10 +727,6 @@ module ActiveRecord #:nodoc:
         @arel_engine = @relation = @arel_table = nil
       end
 
-      def reset_column_information_and_inheritable_attributes_for_all_subclasses#:nodoc:
-        descendants.each { |klass| klass.reset_inheritable_attributes; klass.reset_column_information }
-      end
-
       def attribute_method?(attribute)
         super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, '')))
       end
@@ -736,15 +735,12 @@ module ActiveRecord #:nodoc:
       def lookup_ancestors #:nodoc:
         klass = self
         classes = [klass]
+        return classes if klass == ActiveRecord::Base
+
         while klass != klass.base_class
           classes << klass = klass.superclass
         end
         classes
-      rescue
-        # OPTIMIZE this rescue is to fix this test: ./test/cases/reflection_test.rb:56:in `test_human_name_for_column'
-        # Apparently the method base_class causes some trouble.
-        # It now works for sure.
-        [self]
       end
 
       # Set the i18n scope to overwrite ActiveModel.
@@ -1129,7 +1125,8 @@ MSG
         #   Article.create.published # => true
         def default_scope(options = {})
           reset_scoped_methods
-          self.default_scoping << construct_finder_arel(options, default_scoping.pop)
+          default_scoping = self.default_scoping.dup
+          self.default_scoping = default_scoping << construct_finder_arel(options, default_scoping.pop)
         end
 
         def current_scoped_methods #:nodoc:
@@ -1286,7 +1283,7 @@ MSG
         #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
         def sanitize_sql_array(ary)
           statement, *values = ary
-          if values.first.is_a?(Hash) and statement =~ /:\w+/
+          if values.first.is_a?(Hash) && statement =~ /:\w+/
             replace_named_bind_variables(statement, values.first)
           elsif statement.include?('?')
             replace_bind_variables(statement, values)
@@ -1582,12 +1579,20 @@ MSG
         self.class.columns_hash[name.to_s]
       end
 
-      # Returns true if the +comparison_object+ is the same object, or is of the same type and has the same id.
+      # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
+      # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
+      #
+      # Note that new records are different from any other record by definition, unless the
+      # other record is the receiver itself. Besides, if you fetch existing records with
+      # +select+ and leave the ID out, you're on your own, this predicate will return false.
+      #
+      # Note also that destroying a record preserves its ID in the model instance, so deleted
+      # models are still comparable.
       def ==(comparison_object)
         comparison_object.equal?(self) ||
-          persisted? &&
-            (comparison_object.instance_of?(self.class) &&
-              comparison_object.id == id)
+          comparison_object.instance_of?(self.class) &&
+          id.present? &&
+          comparison_object.id == id
       end
 
       # Delegates to ==
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index f3fba9a3a9..ada1560ce2 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -91,6 +91,11 @@ module ActiveRecord
         false
       end
 
+      # Does this adapter restrict the number of ids you can use in a list. Oracle has a limit of 1000.
+      def ids_in_list_limit
+        nil
+      end
+
       # QUOTING ==================================================
 
       # Override to return the quoted table name. Defaults to column quoting.
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index a4c09b654a..f6321f1499 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -1,6 +1,3 @@
-require 'active_support/core_ext/kernel/singleton_class'
-require 'active_support/core_ext/module/aliasing'
-
 module ActiveRecord
   # Exception that can be raised to stop migrations from going backwards.
   class IrreversibleMigration < ActiveRecordError
@@ -43,11 +40,11 @@ module ActiveRecord
   # Example of a simple migration:
   #
   #   class AddSsl < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       add_column :accounts, :ssl_enabled, :boolean, :default => 1
   #     end
   #
-  #     def self.down
+  #     def down
   #       remove_column :accounts, :ssl_enabled
   #     end
   #   end
@@ -63,7 +60,7 @@ module ActiveRecord
   # Example of a more complex migration that also needs to initialize data:
   #
   #   class AddSystemSettings < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       create_table :system_settings do |t|
   #         t.string  :name
   #         t.string  :label
@@ -77,7 +74,7 @@ module ActiveRecord
   #                             :value => 1
   #     end
   #
-  #     def self.down
+  #     def down
   #       drop_table :system_settings
   #     end
   #   end
@@ -138,7 +135,7 @@ module ActiveRecord
   # in the <tt>db/migrate/</tt> directory where <tt>timestamp</tt> is the
   # UTC formatted date and time that the migration was generated.
   #
-  # You may then edit the <tt>self.up</tt> and <tt>self.down</tt> methods of
+  # You may then edit the <tt>up</tt> and <tt>down</tt> methods of
   # MyNewMigration.
   #
   # There is a special syntactic shortcut to generate migrations that add fields to a table.
@@ -147,11 +144,11 @@ module ActiveRecord
   #
   # This will generate the file <tt>timestamp_add_fieldname_to_tablename</tt>, which will look like this:
   #   class AddFieldnameToTablename < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       add_column :tablenames, :fieldname, :string
   #     end
   #
-  #     def self.down
+  #     def down
   #       remove_column :tablenames, :fieldname
   #     end
   #   end
@@ -179,11 +176,11 @@ module ActiveRecord
   # Not all migrations change the schema. Some just fix the data:
   #
   #   class RemoveEmptyTags < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       Tag.find(:all).each { |tag| tag.destroy if tag.pages.empty? }
   #     end
   #
-  #     def self.down
+  #     def down
   #       # not much we can do to restore deleted data
   #       raise ActiveRecord::IrreversibleMigration, "Can't recover the deleted tags"
   #     end
@@ -192,12 +189,12 @@ module ActiveRecord
   # Others remove columns when they migrate up instead of down:
   #
   #   class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       remove_column :items, :incomplete_items_count
   #       remove_column :items, :completed_items_count
   #     end
   #
-  #     def self.down
+  #     def down
   #       add_column :items, :incomplete_items_count
   #       add_column :items, :completed_items_count
   #     end
@@ -206,11 +203,11 @@ module ActiveRecord
   # And sometimes you need to do something in SQL not abstracted directly by migrations:
   #
   #   class MakeJoinUnique < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       execute "ALTER TABLE `pages_linked_pages` ADD UNIQUE `page_id_linked_page_id` (`page_id`,`linked_page_id`)"
   #     end
   #
-  #     def self.down
+  #     def down
   #       execute "ALTER TABLE `pages_linked_pages` DROP INDEX `page_id_linked_page_id`"
   #     end
   #   end
@@ -223,7 +220,7 @@ module ActiveRecord
   # latest column data from after the new column was added. Example:
   #
   #   class AddPeopleSalary < ActiveRecord::Migration
-  #     def self.up
+  #     def up
   #       add_column :people, :salary, :integer
   #       Person.reset_column_information
   #       Person.find(:all).each do |p|
@@ -243,7 +240,7 @@ module ActiveRecord
   # You can also insert your own messages and benchmarks by using the +say_with_time+
   # method:
   #
-  #   def self.up
+  #   def up
   #     ...
   #     say_with_time "Updating salaries..." do
   #       Person.find(:all).each do |p|
@@ -286,143 +283,201 @@ module ActiveRecord
   #
   # In application.rb.
   #
+  # == Reversible Migrations
+  #
+  # Starting with Rails 3.1, you will be able to define reversible migrations.
+  # Reversible migrations are migrations that know how to go +down+ for you.
+  # You simply supply the +up+ logic, and the Migration system will figure out
+  # how to execute the down commands for you.
+  #
+  # To define a reversible migration, define the +change+ method in your
+  # migration like this:
+  #
+  #   class TenderloveMigration < ActiveRecord::Migration
+  #     def change
+  #       create_table(:horses) do
+  #         t.column :content, :text
+  #         t.column :remind_at, :datetime
+  #       end
+  #     end
+  #   end
+  #
+  # This migration will create the horses table for you on the way up, and
+  # automatically figure out how to drop the table on the way down.
+  #
+  # Some commands like +remove_column+ cannot be reversed.  If you care to
+  # define how to move up and down in these cases, you should define the +up+
+  # and +down+ methods as before.
+  #
+  # If a command cannot be reversed, an
+  # <tt>ActiveRecord::IrreversibleMigration</tt> exception will be raised when
+  # the migration is moving down.
+  #
+  # For a list of commands that are reversible, please see
+  # <tt>ActiveRecord::Migration::CommandRecorder</tt>.
   class Migration
-    @@verbose = true
-    cattr_accessor :verbose
+    autoload :CommandRecorder, 'active_record/migration/command_recorder'
 
     class << self
-      def up_with_benchmarks #:nodoc:
-        migrate(:up)
-      end
+      attr_accessor :delegate # :nodoc:
+    end
 
-      def down_with_benchmarks #:nodoc:
-        migrate(:down)
-      end
+    def self.method_missing(name, *args, &block) # :nodoc:
+      (delegate || superclass.delegate).send(name, *args, &block)
+    end
 
-      # Execute this migration in the named direction
-      def migrate(direction)
-        return unless respond_to?(direction)
+    cattr_accessor :verbose
 
-        case direction
-          when :up   then announce "migrating"
-          when :down then announce "reverting"
-        end
+    attr_accessor :name, :version
 
-        result = nil
-        time = Benchmark.measure { result = send("#{direction}_without_benchmarks") }
+    def initialize
+      @name       = self.class.name
+      @version    = nil
+      @connection = nil
+    end
 
-        case direction
-          when :up   then announce "migrated (%.4fs)" % time.real; write
-          when :down then announce "reverted (%.4fs)" % time.real; write
-        end
+    # instantiate the delegate object after initialize is defined
+    self.verbose  = true
+    self.delegate = new
 
-        result
-      end
+    def up
+      self.class.delegate = self
+      return unless self.class.respond_to?(:up)
+      self.class.up
+    end
+
+    def down
+      self.class.delegate = self
+      return unless self.class.respond_to?(:down)
+      self.class.down
+    end
 
-      # Because the method added may do an alias_method, it can be invoked
-      # recursively. We use @ignore_new_methods as a guard to indicate whether
-      # it is safe for the call to proceed.
-      def singleton_method_added(sym) #:nodoc:
-        return if defined?(@ignore_new_methods) && @ignore_new_methods
+    # Execute this migration in the named direction
+    def migrate(direction)
+      return unless respond_to?(direction)
 
-        begin
-          @ignore_new_methods = true
+      case direction
+      when :up   then announce "migrating"
+      when :down then announce "reverting"
+      end
 
-          case sym
-            when :up, :down
-              singleton_class.send(:alias_method_chain, sym, "benchmarks")
+      time   = nil
+      ActiveRecord::Base.connection_pool.with_connection do |conn|
+        @connection = conn
+        if respond_to?(:change)
+          if direction == :down
+            recorder = CommandRecorder.new(@connection)
+            suppress_messages do
+              @connection = recorder
+              change
+            end
+            @connection = conn
+            time = Benchmark.measure {
+              recorder.inverse.each do |cmd, args|
+                send(cmd, *args)
+              end
+            }
+          else
+            time = Benchmark.measure { change }
           end
-        ensure
-          @ignore_new_methods = false
+        else
+          time = Benchmark.measure { send(direction) }
         end
+        @connection = nil
       end
 
-      def write(text="")
-        puts(text) if verbose
+      case direction
+      when :up   then announce "migrated (%.4fs)" % time.real; write
+      when :down then announce "reverted (%.4fs)" % time.real; write
       end
+    end
 
-      def announce(message)
-        version = defined?(@version) ? @version : nil
+    def write(text="")
+      puts(text) if verbose
+    end
 
-        text = "#{version} #{name}: #{message}"
-        length = [0, 75 - text.length].max
-        write "== %s %s" % [text, "=" * length]
-      end
+    def announce(message)
+      text = "#{version} #{name}: #{message}"
+      length = [0, 75 - text.length].max
+      write "== %s %s" % [text, "=" * length]
+    end
 
-      def say(message, subitem=false)
-        write "#{subitem ? "   ->" : "--"} #{message}"
-      end
+    def say(message, subitem=false)
+      write "#{subitem ? "   ->" : "--"} #{message}"
+    end
 
-      def say_with_time(message)
-        say(message)
-        result = nil
-        time = Benchmark.measure { result = yield }
-        say "%.4fs" % time.real, :subitem
-        say("#{result} rows", :subitem) if result.is_a?(Integer)
-        result
-      end
+    def say_with_time(message)
+      say(message)
+      result = nil
+      time = Benchmark.measure { result = yield }
+      say "%.4fs" % time.real, :subitem
+      say("#{result} rows", :subitem) if result.is_a?(Integer)
+      result
+    end
 
-      def suppress_messages
-        save, self.verbose = verbose, false
-        yield
-      ensure
-        self.verbose = save
-      end
+    def suppress_messages
+      save, self.verbose = verbose, false
+      yield
+    ensure
+      self.verbose = save
+    end
 
-      def connection
-        ActiveRecord::Base.connection
-      end
+    def connection
+      @connection || ActiveRecord::Base.connection
+    end
 
-      def method_missing(method, *arguments, &block)
-        arg_list = arguments.map{ |a| a.inspect } * ', '
+    def method_missing(method, *arguments, &block)
+      arg_list = arguments.map{ |a| a.inspect } * ', '
 
-        say_with_time "#{method}(#{arg_list})" do
-          unless arguments.empty? || method == :execute
-            arguments[0] = Migrator.proper_table_name(arguments.first)
-          end
-          connection.send(method, *arguments, &block)
+      say_with_time "#{method}(#{arg_list})" do
+        unless arguments.empty? || method == :execute
+          arguments[0] = Migrator.proper_table_name(arguments.first)
         end
+        return super unless connection.respond_to?(method)
+        connection.send(method, *arguments, &block)
       end
+    end
 
-      def copy(destination, sources, options = {})
-        copied = []
-
-        destination_migrations = ActiveRecord::Migrator.migrations(destination)
-        last = destination_migrations.last
-        sources.each do |name, path|
-          source_migrations = ActiveRecord::Migrator.migrations(path)
+    def copy(destination, sources, options = {})
+      copied = []
 
-          source_migrations.each do |migration|
-            source = File.read(migration.filename)
-            source = "# This migration comes from #{name} (originally #{migration.version})\n#{source}"
+      FileUtils.mkdir_p(destination) unless File.exists?(destination)
 
-            if duplicate = destination_migrations.detect { |m| m.name == migration.name }
-              options[:on_skip].call(name, migration) if File.read(duplicate.filename) != source && options[:on_skip]
-              next
-            end
+      destination_migrations = ActiveRecord::Migrator.migrations(destination)
+      last = destination_migrations.last
+      sources.each do |name, path|
+        source_migrations = ActiveRecord::Migrator.migrations(path)
 
-            migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
-            new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.rb")
-            old_path, migration.filename = migration.filename, new_path
-            last = migration
+        source_migrations.each do |migration|
+          source = File.read(migration.filename)
+          source = "# This migration comes from #{name} (originally #{migration.version})\n#{source}"
 
-            FileUtils.cp(old_path, migration.filename)
-            copied << migration
-            options[:on_copy].call(name, migration, old_path) if options[:on_copy]
-            destination_migrations << migration
+          if duplicate = destination_migrations.detect { |m| m.name == migration.name }
+            options[:on_skip].call(name, migration) if File.read(duplicate.filename) != source && options[:on_skip]
+            next
           end
-        end
 
-        copied
-      end
+          migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
+          new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.rb")
+          old_path, migration.filename = migration.filename, new_path
+          last = migration
 
-      def next_migration_number(number)
-        if ActiveRecord::Base.timestamped_migrations
-          [Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max
-        else
-          "%.3d" % number
+          FileUtils.cp(old_path, migration.filename)
+          copied << migration
+          options[:on_copy].call(name, migration, old_path) if options[:on_copy]
+          destination_migrations << migration
         end
       end
+
+      copied
+    end
+
+    def next_migration_number(number)
+      if ActiveRecord::Base.timestamped_migrations
+        [Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max
+      else
+        "%.3d" % number
+      end
     end
   end
 
@@ -449,7 +504,7 @@ module ActiveRecord
 
       def load_migration
         require(File.expand_path(filename))
-        name.constantize
+        name.constantize.new
       end
 
   end
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
new file mode 100644
index 0000000000..d7e481905a
--- /dev/null
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -0,0 +1,91 @@
+module ActiveRecord
+  class Migration
+    # ActiveRecord::Migration::CommandRecorder records commands done during
+    # a migration and knows how to reverse those commands.  The CommandRecorder
+    # knows how to invert the following commands:
+    #
+    # * add_column
+    # * add_index
+    # * add_timestamp
+    # * create_table
+    # * remove_timestamps
+    # * rename_column
+    # * rename_index
+    # * rename_table
+    class CommandRecorder
+      attr_accessor :commands, :delegate
+
+      def initialize(delegate = nil)
+        @commands = []
+        @delegate = delegate
+      end
+
+      # record +command+.  +command+ should be a method name and arguments.
+      # For example:
+      #
+      #   recorder.record(:method_name, [:arg1, arg2])
+      def record(*command)
+        @commands << command
+      end
+
+      # Returns a list that represents commands that are the inverse of the
+      # commands stored in +commands+.  For example:
+      #
+      #   recorder.record(:rename_table, [:old, :new])
+      #   recorder.inverse # => [:rename_table, [:new, :old]]
+      #
+      # This method will raise an IrreversibleMigration exception if it cannot
+      # invert the +commands+.
+      def inverse
+        @commands.reverse.map { |name, args|
+          method = :"invert_#{name}"
+          raise IrreversibleMigration unless respond_to?(method, true)
+          __send__(method, args)
+        }
+      end
+
+      def respond_to?(*args) # :nodoc:
+        super || delegate.respond_to?(*args)
+      end
+
+      def send(method, *args) # :nodoc:
+        return super unless respond_to?(method)
+        record(method, args)
+      end
+
+      private
+      def invert_create_table(args)
+        [:drop_table, args]
+      end
+
+      def invert_rename_table(args)
+        [:rename_table, args.reverse]
+      end
+
+      def invert_add_column(args)
+        [:remove_column, args.first(2)]
+      end
+
+      def invert_rename_index(args)
+        [:rename_index, args.reverse]
+      end
+
+      def invert_rename_column(args)
+        [:rename_column, [args.first] + args.last(2).reverse]
+      end
+
+      def invert_add_index(args)
+        table, columns, _ = *args
+        [:remove_index, [table, {:column => columns}]]
+      end
+
+      def invert_remove_timestamps(args)
+        [:add_timestamps, args]
+      end
+
+      def invert_add_timestamps(args)
+        [:remove_timestamps, args]
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index 0b92ba5caa..0f421560f0 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -2,12 +2,18 @@ require 'active_support/core_ext/array'
 require 'active_support/core_ext/hash/except'
 require 'active_support/core_ext/kernel/singleton_class'
 require 'active_support/core_ext/object/blank'
+require 'active_support/core_ext/class/attribute'
 
 module ActiveRecord
   # = Active Record Named \Scopes
   module NamedScope
     extend ActiveSupport::Concern
 
+    included do
+      class_attribute :scopes
+      self.scopes = {}
+    end
+
     module ClassMethods
       # Returns an anonymous \scope.
       #
@@ -33,10 +39,6 @@ module ActiveRecord
         end
       end
 
-      def scopes
-        read_inheritable_attribute(:scopes) || write_inheritable_attribute(:scopes, {})
-      end
-
       # Adds a class method for retrieving and querying objects. A \scope represents a narrowing of a database query,
       # such as <tt>where(:color => :red).select('shirts.*').includes(:washing_instructions)</tt>.
       #
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 0c3392263a..f1d3eaed38 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -2,6 +2,7 @@ require 'active_support/core_ext/hash/except'
 require 'active_support/core_ext/object/try'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/hash/indifferent_access'
+require 'active_support/core_ext/class/attribute'
 
 module ActiveRecord
   module NestedAttributes #:nodoc:
@@ -11,7 +12,7 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_inheritable_accessor :nested_attributes_options, :instance_writer => false
+      class_attribute :nested_attributes_options, :instance_writer => false
       self.nested_attributes_options = {}
     end
 
@@ -268,7 +269,11 @@ module ActiveRecord
           if reflection = reflect_on_association(association_name)
             reflection.options[:autosave] = true
             add_autosave_association_callbacks(reflection)
+
+            nested_attributes_options = self.nested_attributes_options.dup
             nested_attributes_options[association_name.to_sym] = options
+            self.nested_attributes_options = nested_attributes_options
+
             type = (reflection.collection? ? :collection : :one_to_one)
 
             # def pirate_attributes=(attributes)
@@ -315,7 +320,7 @@ module ActiveRecord
     # update_only is true, and a <tt>:_destroy</tt> key set to a truthy value,
     # then the existing record will be marked for destruction.
     def assign_nested_attributes_for_one_to_one_association(association_name, attributes)
-      options = nested_attributes_options[association_name]
+      options = self.nested_attributes_options[association_name]
       attributes = attributes.with_indifferent_access
       check_existing_record = (options[:update_only] || !attributes['id'].blank?)
 
@@ -364,7 +369,7 @@ module ActiveRecord
     #     { :id => '2', :_destroy => true }
     #   ])
     def assign_nested_attributes_for_collection_association(association_name, attributes_collection)
-      options = nested_attributes_options[association_name]
+      options = self.nested_attributes_options[association_name]
 
       unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
         raise ArgumentError, "Hash or Array expected, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
@@ -433,7 +438,7 @@ module ActiveRecord
     end
 
     def call_reject_if(association_name, attributes)
-      case callback = nested_attributes_options[association_name][:reject_if]
+      case callback = self.nested_attributes_options[association_name][:reject_if]
       when Symbol
         method(callback).arity == 0 ? send(callback) : send(callback, attributes)
       when Proc
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index a2260e9a19..a07c321960 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -1,8 +1,15 @@
+require 'active_support/core_ext/class/attribute'
+
 module ActiveRecord
   # = Active Record Reflection
   module Reflection # :nodoc:
     extend ActiveSupport::Concern
 
+    included do
+      class_attribute :reflections
+      self.reflections = {}
+    end
+
     # Reflection enables to interrogate Active Record classes and objects
     # about their associations and aggregations. This information can,
     # for example, be used in a form builder that takes an Active Record object
@@ -20,18 +27,9 @@ module ActiveRecord
           when :composed_of
             reflection = AggregateReflection.new(macro, name, options, active_record)
         end
-        write_inheritable_hash :reflections, name => reflection
-        reflection
-      end
 
-      # Returns a hash containing all AssociationReflection objects for the current class.
-      # Example:
-      #
-      #   Invoice.reflections
-      #   Account.reflections
-      #
-      def reflections
-        read_inheritable_attribute(:reflections) || write_inheritable_attribute(:reflections, {})
+        self.reflections = self.reflections.merge(name => reflection)
+        reflection
       end
 
       # Returns an array of AggregateReflection objects for all the aggregations in the class.
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index 6bf698fe97..c8adaddfca 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -208,14 +208,16 @@ module ActiveRecord
     end
 
     def execute_grouped_calculation(operation, column_name, distinct) #:nodoc:
-      group_attr      = @group_values.first
-      association     = @klass.reflect_on_association(group_attr.to_sym)
-      associated      = association && association.macro == :belongs_to # only count belongs_to associations
-      group_field     = associated ? association.primary_key_name : group_attr
-      group_alias     = column_alias_for(group_field)
-      group_column    = column_for(group_field)
+      group_attr      = @group_values
+      association     = @klass.reflect_on_association(group_attr.first.to_sym)
+      associated      = group_attr.size == 1 && association && association.macro == :belongs_to # only count belongs_to associations
+      group_fields  = Array(associated ? association.primary_key_name : group_attr)
+      group_aliases = group_fields.map { |field| column_alias_for(field) }
+      group_columns = group_aliases.zip(group_fields).map { |aliaz,field|
+        [aliaz, column_for(field)]
+      }
 
-      group = @klass.connection.adapter_name == 'FrontBase' ? group_alias : group_field
+      group = @klass.connection.adapter_name == 'FrontBase' ? group_aliases : group_fields
 
       if operation == 'count' && column_name == :all
         aggregate_alias = 'count_all'
@@ -223,22 +225,33 @@ module ActiveRecord
         aggregate_alias = column_alias_for(operation, column_name)
       end
 
-      relation = except(:group).group(group)
-      relation.select_values = [
-        operation_over_aggregate_column(aggregate_column(column_name), operation, distinct).as(aggregate_alias),
-        "#{group_field} AS #{group_alias}"
+      select_values = [
+        operation_over_aggregate_column(
+          aggregate_column(column_name),
+          operation,
+          distinct).as(aggregate_alias)
       ]
 
+      select_values.concat group_fields.zip(group_aliases).map { |field,aliaz|
+        "#{field} AS #{aliaz}"
+      }
+
+      relation = except(:group).group(group.join(','))
+      relation.select_values = select_values
+
       calculated_data = @klass.connection.select_all(relation.to_sql)
 
       if association
-        key_ids     = calculated_data.collect { |row| row[group_alias] }
+        key_ids     = calculated_data.collect { |row| row[group_aliases.first] }
         key_records = association.klass.base_class.find(key_ids)
         key_records = Hash[key_records.map { |r| [r.id, r] }]
       end
 
       ActiveSupport::OrderedHash[calculated_data.map do |row|
-        key = type_cast_calculated_value(row[group_alias], group_column)
+        key   = group_columns.map { |aliaz, column|
+          type_cast_calculated_value(row[aliaz], column)
+        }
+        key   = key.first if key.size == 1
         key = key_records[key] if associated
         [key, type_cast_calculated_value(row[aggregate_alias], column_for(column_name), operation)]
       end]
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index c5428dccd6..32c7d08daa 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -25,6 +25,11 @@ module ActiveRecord
             attribute.in(values)
           when Range, Arel::Relation
             attribute.in(value)
+          when ActiveRecord::Base
+            attribute.eq(value.quoted_id)
+          when Class
+            # FIXME: I think we need to deprecate this behavior
+            attribute.eq(value.name)
           else
             attribute.eq(value)
           end
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 9c399d3333..9e7503a60d 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -141,7 +141,7 @@ module ActiveRecord
         "#{@klass.table_name}.#{@klass.primary_key} DESC" :
         reverse_sql_order(order_clause).join(', ')
 
-      except(:order).order(Arel::SqlLiteral.new(order))
+      except(:order).order(Arel.sql(order))
     end
 
     def arel
@@ -174,10 +174,7 @@ module ActiveRecord
 
       arel = build_joins(arel, @joins_values) unless @joins_values.empty?
 
-      (@where_values - ['']).uniq.each do |where|
-        where = Arel.sql(where) if String === where
-        arel = arel.where(Arel::Nodes::Grouping.new(where))
-      end
+      arel = collapse_wheres(arel, (@where_values - ['']).uniq)
 
       arel = arel.having(*@having_values.uniq.reject{|h| h.blank?}) unless @having_values.empty?
 
@@ -198,6 +195,27 @@ module ActiveRecord
 
     private
 
+    def collapse_wheres(arel, wheres)
+      equalities = wheres.grep(Arel::Nodes::Equality)
+
+      groups = equalities.group_by do |equality|
+        equality.left
+      end
+
+      groups.each do |_, eqls|
+        test = eqls.inject(eqls.shift) do |memo, expr|
+          memo.or(expr)
+        end
+        arel = arel.where(test)
+      end
+
+      (wheres - equalities).each do |where|
+        where = Arel.sql(where) if String === where
+        arel = arel.where(Arel::Nodes::Grouping.new(where))
+      end
+      arel
+    end
+
     def build_where(opts, other = [])
       case opts
       when String, Array
diff --git a/activerecord/lib/active_record/schema.rb b/activerecord/lib/active_record/schema.rb
index c1bc3214ea..c6bb5c1961 100644
--- a/activerecord/lib/active_record/schema.rb
+++ b/activerecord/lib/active_record/schema.rb
@@ -30,9 +30,7 @@ module ActiveRecord
   # ActiveRecord::Schema is only supported by database adapters that also
   # support migrations, the two features being very similar.
   class Schema < Migration
-    private_class_method :new
-
-    def self.migrations_path
+    def migrations_path
       ActiveRecord::Migrator.migrations_path
     end
 
@@ -48,11 +46,12 @@ module ActiveRecord
     #     ...
     #   end
     def self.define(info={}, &block)
-      instance_eval(&block)
+      schema = new
+      schema.instance_eval(&block)
 
       unless info[:version].blank?
         initialize_schema_migrations_table
-        assume_migrated_upto_version(info[:version], migrations_path)
+        assume_migrated_upto_version(info[:version], schema.migrations_path)
       end
     end
   end
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index 230adf6b2b..2ecbd906bd 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/class/attribute'
+
 module ActiveRecord
   # = Active Record Timestamp
   #
@@ -29,14 +31,14 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_inheritable_accessor :record_timestamps, :instance_writer => false
+      class_attribute :record_timestamps, :instance_writer => false
       self.record_timestamps = true
     end
 
   private
 
     def create #:nodoc:
-      if record_timestamps
+      if self.record_timestamps
         current_time = current_time_from_proper_timezone
 
         all_timestamp_attributes.each do |column|
@@ -61,7 +63,7 @@ module ActiveRecord
     end
 
     def should_record_timestamps?
-      record_timestamps && (!partial_updates? || changed? || (attributes.keys & self.class.serialized_attributes.keys).present?)
+      self.record_timestamps && (!partial_updates? || changed? || (attributes.keys & self.class.serialized_attributes.keys).present?)
     end
 
     def timestamp_attributes_for_update_in_model
diff --git a/activerecord/lib/active_record/version.rb b/activerecord/lib/active_record/version.rb
index 89eba15be1..0667be7d23 100644
--- a/activerecord/lib/active_record/version.rb
+++ b/activerecord/lib/active_record/version.rb
@@ -3,8 +3,8 @@ module ActiveRecord
     MAJOR = 3
     MINOR = 1
     TINY  = 0
-    BUILD = "beta"
+    PRE   = "beta"
 
-    STRING = [MAJOR, MINOR, TINY, BUILD].join('.')
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end
 end
diff --git a/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
index 8ac21c1410..126b6f434b 100644
--- a/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/migration/templates/migration.rb
@@ -1,5 +1,5 @@
 class <%= migration_class_name %> < ActiveRecord::Migration
-  def self.up
+  def up
 <% attributes.each do |attribute| -%>
   <%- if migration_action -%>
     <%= migration_action %>_column :<%= table_name %>, :<%= attribute.name %><% if migration_action == 'add' %>, :<%= attribute.type %><% end %>
@@ -7,7 +7,7 @@ class <%= migration_class_name %> < ActiveRecord::Migration
 <%- end -%>
   end
 
-  def self.down
+  def down
 <% attributes.reverse.each do |attribute| -%>
   <%- if migration_action -%>
     <%= migration_action == 'add' ? 'remove' : 'add' %>_column :<%= table_name %>, :<%= attribute.name %><% if migration_action == 'remove' %>, :<%= attribute.type %><% end %>
diff --git a/activerecord/lib/rails/generators/active_record/model/templates/migration.rb b/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
index 1f68487304..70e064be21 100644
--- a/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
@@ -1,5 +1,5 @@
 class <%= migration_class_name %> < ActiveRecord::Migration
-  def self.up
+  def up
     create_table :<%= table_name %> do |t|
 <% for attribute in attributes -%>
       t.<%= attribute.type %> :<%= attribute.name %>
@@ -10,7 +10,7 @@ class <%= migration_class_name %> < ActiveRecord::Migration
     end
   end
 
-  def self.down
+  def down
     drop_table :<%= table_name %>
   end
 end
diff --git a/activerecord/lib/rails/generators/active_record/session_migration/templates/migration.rb b/activerecord/lib/rails/generators/active_record/session_migration/templates/migration.rb
index 919822af7b..8f0bf1ef0d 100644
--- a/activerecord/lib/rails/generators/active_record/session_migration/templates/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/session_migration/templates/migration.rb
@@ -1,5 +1,5 @@
 class <%= migration_class_name %> < ActiveRecord::Migration
-  def self.up
+  def up
     create_table :<%= session_table_name %> do |t|
       t.string :session_id, :null => false
       t.text :data
@@ -10,7 +10,7 @@ class <%= migration_class_name %> < ActiveRecord::Migration
     add_index :<%= session_table_name %>, :updated_at
   end
 
-  def self.down
+  def down
     drop_table :<%= session_table_name %>
   end
 end