13 files changed, 226 insertions, 50 deletions
diff --git a/guides/CHANGELOG.md b/guides/CHANGELOG.md
index 99d69d5eda..dd5ca4b395 100644
--- a/guides/CHANGELOG.md
+++ b/guides/CHANGELOG.md
@@ -6,4 +6,8 @@
 
     *Andrey Nering*
 
+*   New section in Configuring: Search Engines Indexing
+
+    *Andrey Nering*
+
 Please check [4-2-stable](https://github.com/rails/rails/blob/4-2-stable/guides/CHANGELOG.md) for previous changes.
diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md
index 80000baf66..f68179841e 100644
--- a/guides/source/action_controller_overview.md
+++ b/guides/source/action_controller_overview.md
@@ -737,7 +737,7 @@ You can choose not to yield and build the response yourself, in which case the a
 
 While the most common way to use filters is by creating private methods and using *_action to add them, there are two other ways to do the same thing.
 
-The first is to use a block directly with the *_action methods. The block receives the controller as an argument, and the `require_login` filter from above could be rewritten to use a block:
+The first is to use a block directly with the *\_action methods. The block receives the controller as an argument, and the `require_login` filter from above could be rewritten to use a block:
 
 ```ruby
 class ApplicationController < ActionController::Base
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
index 665a2b71ff..d3a2e15c61 100644
--- a/guides/source/action_view_overview.md
+++ b/guides/source/action_view_overview.md
@@ -190,6 +190,22 @@ One way to use partials is to treat them as the equivalent of subroutines; a way
 
 Here, the `_ad_banner.html.erb` and `_footer.html.erb` partials could contain content that is shared among many pages in your application. You don't need to see the details of these sections when you're concentrating on a particular page.
 
+#### `render` without `partial` and `locals` options
+
+In the above example, `render` takes 2 options: `partial` and `locals`. But if
+these are the only options you want to pass, you can skip using these options.
+For example, instead of:
+
+```erb
+<%= render partial: "product", locals: {product: @product} %>
+```
+
+You can also do:
+
+```erb
+<%= render "product", product: @product %>
+```
+
 #### The `as` and `object` options
 
 By default `ActionView::Partials::PartialRenderer` has its object in a local variable with the same name as the template. So, given:
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index 373a98bb85..ad5103da69 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -317,7 +317,7 @@ end
 
 The `find_each` method accepts most of the options allowed by the regular `find` method, except for `:order` and `:limit`, which are reserved for internal use by `find_each`.
 
-Two additional options, `:batch_size` and `:start`, are available as well.
+Two additional options, `:batch_size` and `:begin_at`, are available as well.
 
 **`:batch_size`**
 
@@ -329,19 +329,32 @@ User.find_each(batch_size: 5000) do |user|
 end
 ```
 
-**`:start`**
+**`:begin_at`**
 
-By default, records are fetched in ascending order of the primary key, which must be an integer. The `:start` option allows you to configure the first ID of the sequence whenever the lowest ID is not the one you need. This would be useful, for example, if you wanted to resume an interrupted batch process, provided you saved the last processed ID as a checkpoint.
+By default, records are fetched in ascending order of the primary key, which must be an integer. The `:begin_at` option allows you to configure the first ID of the sequence whenever the lowest ID is not the one you need. This would be useful, for example, if you wanted to resume an interrupted batch process, provided you saved the last processed ID as a checkpoint.
 
 For example, to send newsletters only to users with the primary key starting from 2000, and to retrieve them in batches of 5000:
 
 ```ruby
-User.find_each(start: 2000, batch_size: 5000) do |user|
+User.find_each(begin_at: 2000, batch_size: 5000) do |user|
   NewsMailer.weekly(user).deliver_now
 end
 ```
 
-Another example would be if you wanted multiple workers handling the same processing queue. You could have each worker handle 10000 records by setting the appropriate `:start` option on each worker.
+Another example would be if you wanted multiple workers handling the same processing queue. You could have each worker handle 10000 records by setting the appropriate `:begin_at` option on each worker.
+
+**`:end_at`**
+
+Similar to the `:begin_at` option, `:end_at` allows you to configure the last ID of the sequence whenever the highest ID is not the one you need.
+This would be useful, for example, if you wanted to run a batch process, using a subset of records based on `:begin_at` and `:end_at`
+
+For example, to send newsletters only to users with the primary key starting from 2000 upto 10000 and to retrieve them in batches of 1000:
+
+```ruby
+User.find_each(begin_at: 2000, end_at: 10000, batch_size: 5000) do |user|
+  NewsMailer.weekly(user).deliver_now
+end
+```
 
 #### `find_in_batches`
 
@@ -356,7 +369,7 @@ end
 
 ##### Options for `find_in_batches`
 
-The `find_in_batches` method accepts the same `:batch_size` and `:start` options as `find_each`.
+The `find_in_batches` method accepts the same `:batch_size`, `:begin_at` and `:end_at` options as `find_each`.
 
 Conditions
 ----------
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
index 67cc6a4db3..de26a9bd6d 100644
--- a/guides/source/active_record_validations.md
+++ b/guides/source/active_record_validations.md
@@ -231,9 +231,9 @@ Errors](#working-with-validation-errors) section.
 
 ### `errors.details`
 
-To check what validator type was used on invalid attribute, you can use
-`errors.details[:attribute]`. It returns array of hashes where under `:error`
- key you will find symbol of used validator.
+To check which validations failed on an invalid attribute, you can use
+`errors.details[:attribute]`. It returns an array of hashes with an `:error`
+key to get the symbol of the validator:
 
 ```ruby
 class Person < ActiveRecord::Base
@@ -245,7 +245,7 @@ end
 >> person.errors.details[:name] #=> [{error: :blank}]
 ```
 
-Using `details` with custom validators are covered in the [Working with
+Using `details` with custom validators is covered in the [Working with
 Validation Errors](#working-with-validation-errors) section.
 
 Validation Helpers
@@ -606,9 +606,7 @@ This helper validates that the attribute's value is unique right before the
 object gets saved. It does not create a uniqueness constraint in the database,
 so it may happen that two different database connections create two records
 with the same value for a column that you intend to be unique. To avoid that,
-you must create a unique index on both columns in your database. See
-[the MySQL manual](http://dev.mysql.com/doc/refman/5.6/en/multiple-column-indexes.html)
-for more details about multiple column indexes.
+you must create a unique index on that column in your database.
 
 ```ruby
 class Account < ActiveRecord::Base
@@ -628,6 +626,7 @@ class Holiday < ActiveRecord::Base
     message: "should happen once per year" }
 end
 ```
+Should you wish to create a database constraint to prevent possible violations of a uniqueness validation using the `:scope` option, you must create a unique index on both columns in your database. See [the MySQL manual](http://dev.mysql.com/doc/refman/5.6/en/multiple-column-indexes.html) for more details about multiple column indexes or [the PostgreSQL manual](http://www.postgresql.org/docs/9.4/static/ddl-constraints.html) for examples of unique constraints that refer to a group of columns.
 
 There is also a `:case_sensitive` option that you can use to define whether the
 uniqueness constraint will be case sensitive or not. This option defaults to
@@ -1094,39 +1093,40 @@ Another way to do this is using `[]=` setter
 
 ### `errors.details`
 
-You can add validator type to details hash when using `errors.add` method.
+You can specify a validator type to the returned error details hash using the
+`errors.add` method.
 
 ```ruby
-  class Person < ActiveRecord::Base
-    def a_method_used_for_validation_purposes
-      errors.add(:name, :invalid_characters)
-    end
+class Person < ActiveRecord::Base
+  def a_method_used_for_validation_purposes
+    errors.add(:name, :invalid_characters)
   end
+end
 
-  person = Person.create(name: "!@#")
+person = Person.create(name: "!@#")
 
-  person.errors.details[:name]
-   # => [{error: :invalid_characters}]
+person.errors.details[:name]
+# => [{error: :invalid_characters}]
 ```
 
-To improve error details to contain not allowed characters set, you can
-pass additional options to `errors.add` method.
+To improve the error details to contain the unallowed characters set for instance,
+you can pass additional keys to `errors.add`.
 
 ```ruby
-  class Person < ActiveRecord::Base
-    def a_method_used_for_validation_purposes
-      errors.add(:name, :invalid_characters, not_allowed: "!@#%*()_-+=")
-    end
+class Person < ActiveRecord::Base
+  def a_method_used_for_validation_purposes
+    errors.add(:name, :invalid_characters, not_allowed: "!@#%*()_-+=")
   end
+end
 
-  person = Person.create(name: "!@#")
+person = Person.create(name: "!@#")
 
-  person.errors.details[:name]
-  # => [{error: :invalid_characters, not_allowed: "!@#%*()_-+="}]
+person.errors.details[:name]
+# => [{error: :invalid_characters, not_allowed: "!@#%*()_-+="}]
 ```
 
-All built in Rails validators populate details hash with corresponding
-validator types.
+All built in Rails validators populate the details hash with the corresponding
+validator type.
 
 ### `errors[:base]`
 
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md
index 8633cc4f10..3484627a78 100644
--- a/guides/source/association_basics.md
+++ b/guides/source/association_basics.md
@@ -171,7 +171,7 @@ class CreateCustomers < ActiveRecord::Migration
     end
 
     create_table :orders do |t|
-      t.belongs_to :customer, index:true
+      t.belongs_to :customer, index: true
       t.datetime :order_date
       t.timestamps null: false
     end
@@ -691,7 +691,7 @@ c.first_name = 'Manny'
 c.first_name == o.customer.first_name # => false
 ```
 
-This happens because c and o.customer are two different in-memory representations of the same data, and neither one is automatically refreshed from changes to the other. Active Record provides the `:inverse_of` option so that you can inform it of these relations:
+This happens because `c` and `o.customer` are two different in-memory representations of the same data, and neither one is automatically refreshed from changes to the other. Active Record provides the `:inverse_of` option so that you can inform it of these relations:
 
 ```ruby
 class Customer < ActiveRecord::Base
@@ -726,10 +726,10 @@ Most associations with standard names will be supported. However, associations
 that contain the following options will not have their inverses set
 automatically:
 
-* :conditions
-* :through
-* :polymorphic
-* :foreign_key
+* `:conditions`
+* `:through`
+* `:polymorphic`
+* `:foreign_key`
 
 Detailed Association Reference
 ------------------------------
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 9c0f2ddc8a..994cc31cff 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -1049,3 +1049,21 @@ These configuration points are then available through the configuration object:
   Rails.configuration.x.super_debugger              # => true
   Rails.configuration.x.super_debugger.not_set      # => nil
   ```
+
+Search Engines Indexing
+-----------------------
+
+Sometimes, you may want to prevent some pages of your application be visible on search sites like Google,
+Bing, Yahoo or Duck Duck Go. The robots that index these sites will first analyse the
+`https://your-site.com/robots.txt` file to know what pages it is allowed to index.
+
+Rails creates this file for you on `/public` folder. By default, it allows search engines to index all
+pages of your application. If you want to block indexing on all pages of you application, use this:
+
+```
+User-agent: *
+Disallow: /
+```
+
+To block just specific pages, it's necessary to use a more complex syntax. Learn it on the
+[official documentation](http://www.robotstxt.org/robotstxt.html).
diff --git a/guides/source/debugging_rails_applications.md b/guides/source/debugging_rails_applications.md
index f6e7980fe2..6113a61f4c 100644
--- a/guides/source/debugging_rails_applications.md
+++ b/guides/source/debugging_rails_applications.md
@@ -242,6 +242,58 @@ The contents of the block, and therefore the string interpolation, is only
 evaluated if debug is enabled. This performance savings is only really
 noticeable with large amounts of logging, but it's a good practice to employ.
 
+
+Debugging with the `web-console` gem
+-------------------------------------
+
+The web console allows you to create an interactive ruby session in your browser. An interactive 
+console is launched automatically in case on an error but can also be launched for debugging purposes
+by invoking `console` in a view or controller.
+
+For example in a view:
+
+```ruby
+# new.html.erb
+<%= console %>
+```
+
+Or in a controller:
+
+```ruby
+# posts_controller.rb
+class PostsController < ApplicationController
+  def new
+    console
+    @post = Post.new
+  end
+end
+```
+###config.web_console.whitelisted_ips
+
+By default the web console can only be accessed from localhost. `config.web_console.whitelisted_ips` 
+lets you control which IPs have access to the console. 
+
+For example, to allow access from both localhost and 192.168.0.100:
+
+```ruby
+# config/application.rb
+class Application < Rails::Application
+  config.web_console.whitelisted_ips = %w( 127.0.0.1 192.168.0.100 )
+end
+```
+
+To allow access from an entire network:
+
+```ruby
+# config/application.rb
+class Application < Rails::Application
+  config.web_console.whitelisted_ips = %w( 127.0.0.1 192.168.0.0/16 )
+end
+```
+
+Web console is a powerful tool so be careful who you open access to.
+
+
 Debugging with the `byebug` gem
 ---------------------------------
 
@@ -832,7 +884,7 @@ application. Here is a list of useful plugins for debugging:
 * [Footnotes](https://github.com/josevalim/rails-footnotes) Every Rails page has
 footnotes that give request information and link back to your source via
 TextMate.
-* [Query Trace](https://github.com/ntalbott/query_trace/tree/master) Adds query
+* [Query Trace](https://github.com/ruckus/active-record-query-trace/tree/master) Adds query
 origin tracing to your logs.
 * [Query Reviewer](https://github.com/nesquena/query_reviewer) This rails plugin
 not only runs "EXPLAIN" before each of your select queries in development, but
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
index fbee267975..9b049ea8b8 100644
--- a/guides/source/i18n.md
+++ b/guides/source/i18n.md
@@ -588,6 +588,26 @@ you can look up the `books.index.title` value **inside** `app/views/books/index.
 
 NOTE: Automatic translation scoping by partial is only available from the `translate` view helper method.
 
+"Lazy" lookup can also be used in controllers:
+
+```yaml
+en:
+  books:
+    create:
+      success: Book created!
+```
+
+This is useful for setting flash messages for instance:
+
+```ruby
+class BooksController < ApplicationController
+  def create
+    # ...
+    redirect_to books_url, notice: t('.success')
+  end
+end
+```
+
 ### Interpolation
 
 In many cases you want to abstract your translations so that **variables can be interpolated into the translation**. For this reason the I18n API provides an interpolation feature.
diff --git a/guides/source/layouts_and_rendering.md b/guides/source/layouts_and_rendering.md
index 69d3f6e86c..b7fc580939 100644
--- a/guides/source/layouts_and_rendering.md
+++ b/guides/source/layouts_and_rendering.md
@@ -1049,7 +1049,7 @@ As you already could see from the previous sections of this guide, `yield` is a
       <p>
         Name contains: <%= f.text_field :name_contains %>
       </p>
-    <%= end %>
+    <% end %>
     ```
 
 * `roles/index.html.erb`
@@ -1059,7 +1059,7 @@ As you already could see from the previous sections of this guide, `yield` is a
       <p>
         Title contains: <%= f.text_field :title_contains %>
       </p>
-    <%= end %>
+    <% end %>
     ```
 
 * `shared/_search_filters.html.erb`
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 7345c7f522..14bc75aa7d 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -120,9 +120,9 @@ user_<%= n %>:
 
 Rails by default automatically loads all fixtures from the `test/fixtures` directory for your models and controllers test. Loading involves three steps:
 
-* Remove any existing data from the table corresponding to the fixture
-* Load the fixture data into the table
-* Dump the fixture data into a method in case you want to access it directly
+1. Remove any existing data from the table corresponding to the fixture
+2. Load the fixture data into the table
+3. Dump the fixture data into a method in case you want to access it directly
 
 TIP: In order to remove existing data from the database, Rails tries to disable referential integrity triggers (like foreign keys and check constraints). If you are getting annoying permission errors on running tests, make sure the database user has privilege to disable these triggers in testing environment. (In PostgreSQL, only superusers can disable all triggers. Read more about PostgreSQL permissions [here](http://blog.endpoint.com/2012/10/postgres-system-triggers-error.html))
 
@@ -270,6 +270,8 @@ Finished tests in 0.009262s, 107.9680 tests/s, 107.9680 assertions/s.
 1 tests, 1 assertions, 0 failures, 0 errors, 0 skips
 ```
 
+This will run all test methods from the test case.
+
 You can also run a particular test method from the test case by running the test and providing the `test method name`.
 
 ```bash
@@ -281,8 +283,6 @@ Finished tests in 0.009064s, 110.3266 tests/s, 110.3266 assertions/s.
 1 tests, 1 assertions, 0 failures, 0 errors, 0 skips
 ```
 
-This will run all test methods from the test case.
-
 The `.` (dot) above indicates a passing test. When a test fails you see an `F`; when a test throws an error you see an `E` in its place. The last line of the output is the summary.
 
 #### Your first failing test
@@ -347,7 +347,11 @@ Finished tests in 0.047721s, 20.9551 tests/s, 20.9551 assertions/s.
 1 tests, 1 assertions, 0 failures, 0 errors, 0 skips
 ```
 
-Now, if you noticed, we first wrote a test which fails for a desired functionality, then we wrote some code which adds the functionality and finally we ensured that our test passes. This approach to software development is referred to as _Test-Driven Development_ (TDD).
+Now, if you noticed, we first wrote a test which fails for a desired
+functionality, then we wrote some code which adds the functionality and finally
+we ensured that our test passes. This approach to software development is
+referred to as
+[_Test-Driven Development_ (TDD)](http://c2.com/cgi/wiki?TestDrivenDevelopment).
 
 #### What an error looks like
 
@@ -379,7 +383,11 @@ NameError: undefined local variable or method `some_undefined_variable' for #<Ar
 
 Notice the 'E' in the output. It denotes a test with error.
 
-NOTE: The execution of each test method stops as soon as any error or an assertion failure is encountered, and the test suite continues with the next method. All test methods are executed in alphabetical order.
+NOTE: The execution of each test method stops as soon as any error or an
+assertion failure is encountered, and the test suite continues with the next
+method. All test methods are executed in random order. The
+[`config.active_support.test_order` option](http://edgeguides.rubyonrails.org/configuring.html#configuring-active-support)
+can be used to configure test order.
 
 When a test fails you are presented with the corresponding backtrace. By default
 Rails filters that backtrace and will only print lines relevant to your
@@ -537,7 +545,8 @@ NOTE: Functional tests do not verify whether the specified request type is accep
 
 ### Testing XHR (AJAX) requests
 
-Enable set  `xhr: true` option as an argument to `get/post/patch/put/delete` method:
+To test AJAX requests, you can specify the `xhr: true` option to `get`, `post`,
+`patch`, `put`, and `delete` methods:
 
 ```ruby
 test "ajax request responds with no layout" do
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 909a92b9dd..20b90bdba0 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -276,6 +276,22 @@ class Notifier < ActionMailer::Base
 end
 ```
 
+### Foreign Key Support
+
+The migration DSL has been expanded to support foreign key definitions. If
+you've been using the Foreigner gem, you might want to consider removing it.
+Note that the foreign key support of Rails is a subset of Foreigner. This means
+that not every Foreigner definition can be fully replaced by it's Rails
+migration DSL counterpart.
+
+The migration procedure is as follows:
+
+1. remove `gem "foreigner"` from the Gemfile.
+2. run `bundle install`.
+3. run `bin/rake db:schema:dump`.
+4. make sure that `db/schema.rb` contains every foreign key definition with
+the necessary options.
+
 Upgrading from Rails 4.0 to Rails 4.1
 -------------------------------------
 
diff --git a/guides/source/working_with_javascript_in_rails.md b/guides/source/working_with_javascript_in_rails.md
index f3d3a83afc..e3856a285a 100644
--- a/guides/source/working_with_javascript_in_rails.md
+++ b/guides/source/working_with_javascript_in_rails.md
@@ -191,6 +191,34 @@ $(document).ready ->
 Obviously, you'll want to be a bit more sophisticated than that, but it's a
 start. You can see more about the events [in the jquery-ujs wiki](https://github.com/rails/jquery-ujs/wiki/ajax).
 
+Another possibility is returning javascript directly from the server side on
+remote calls:
+
+```ruby
+# articles_controller
+def create
+  respond_to do |format|
+    if @article.save
+      format.html { ... }
+      format.js do
+        render js: <<-endjs
+          alert('Article saved successfully!');
+          window.location = '#{article_path(@article)}';
+        endjs
+      end
+    else
+      format.html { ... }
+      format.js do
+        render js: "alert('There are empty fields in the form!');"
+      end
+    end
+  end
+end
+```
+
+NOTE: If javascript is disabled in the user browser, `format.html { ... }`
+block should be executed as fallback.
+
 ### form_tag
 
 [`form_tag`](http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html#method-i-form_tag)