Use the new `foreign_key` option on `references` in generators

Changes `rails g model Post user:references` from

    def change
      create_table :posts do |t|
        t.references :user, index: true
      end

      add_foreign_key :posts, :users
    end

to

    def change
      create_table :posts do |t|
        t.references :user, index: true, foreign_key: true
      end
    end

Changes `rails g migration add_user_to_posts user:references` from

    def change
      add_reference :posts, :users, index: true
      add_foreign_key :posts, :users
    end

to

    def change
      add_reference :posts, :users, index: true, foreign_key: true
    end

1 files changed, 4 insertions, 0 deletions

diff --git a/railties/lib/rails/generators/generated_attribute.rb b/railties/lib/rails/generators/generated_attribute.rb
index f16bd8e082..77a3dbf9a2 100644
--- a/railties/lib/rails/generators/generated_attribute.rb
+++ b/railties/lib/rails/generators/generated_attribute.rb
@@ -159,6 +159,10 @@ module Rails
             options.delete(:required)
             options[:null] = false
           end
+
+          if reference? && !polymorphic?
+            options[:foreign_key] = true
+          end
         end
       end
     end