# File lib/generators/active_record/devise_generator.rb, line 13
      def copy_devise_migration
        if (behavior == :invoke && model_exists?) || (behavior == :revoke && migration_exists?(table_name))
          migration_template "migration_existing.rb", "db/migrate/add_devise_to_#{table_name}"
        else
          migration_template "migration.rb", "db/migrate/devise_create_#{table_name}"
        end
      end