class MakeGroupsUsersAModel < ActiveRecord::Migration def self.up remove_index :groups_users, :name => :groups_users_ids rename_table :groups_users, :group_users add_index :group_users, [:group_id, :user_id], :name => :group_user_ids, :unique => true end def self.down remove_index :group_users, :name => :group_user_ids rename_table :group_users, :groups_users add_index :groups_users, [:group_id, :user_id], :name => :groups_users_ids, :unique => true end end