Generate add_index by default when giving type belongs_to or references

2 files changed, 26 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 9c2e311c75..056de18cde 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,27 @@
 *Rails 3.1.0 (unreleased)*
 
+* When a model is generated add_index is added by default for belongs_to or references columns 
+
+  rails g model post user:belongs_to will generate the following:
+
+    class CreatePosts < ActiveRecord::Migration
+      def up
+        create_table :posts do |t|
+          t.belongs_to :user
+
+          t.timestamps
+        end
+
+        add_index :posts, :user_id
+      end
+
+      def down
+        drop_table :posts
+      end
+    end
+
+  [Santiago Pastorino]
+
 * Setting the id of a belongs_to object will update the reference to the
 object. [#2989 state:resolved]
 
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 70e064be21..7d4e1a7404 100644
--- a/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/model/templates/migration.rb
@@ -8,6 +8,10 @@ class <%= migration_class_name %> < ActiveRecord::Migration
       t.timestamps
 <% end -%>
     end
+
+<% attributes.select {|attr| attr.reference? }.each do |attribute| -%>
+    add_index :<%= table_name %>, :<%= attribute.name %>_id
+<% end -%>
   end
 
   def down