perform_down (DataMapper::Migration)

    # File lib/dm-migrations/migration.rb, line 66
        def perform_down
          result = nil
          if needs_down?
            # TODO: fix this so it only does transactions for databases that support create/drop
            # database.transaction.commit do
              say_with_time "== Performing Down Migration ##{position}: #{name}", 0 do
                result = @down_action.call
              end
              update_migration_info(:down)
            # end
          end
          result
        end