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

1 files changed, 5 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 0952ea2829..34684ad2f5 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1424,18 +1424,18 @@ module ActiveRecord
       # join table with a migration such as this:
       #
       #   class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration
-      #     def self.up
+      #     def change
       #       create_table :developers_projects, :id => false do |t|
       #         t.integer :developer_id
       #         t.integer :project_id
       #       end
       #     end
-      #
-      #     def self.down
-      #       drop_table :developers_projects
-      #     end
       #   end
       #
+      # It's also a good idea to add indexes to each of those columns to speed up the joins process.
+      # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only
+      # uses one index per table during the lookup.
+      #
       # Adds the following methods for retrieval and query:
       #
       # [collection(force_reload = false)]