class ActiveRecord::MigrationContext

def move(direction, steps)
  migrator = Migrator.new(direction, migrations, schema_migration)
  if current_version != 0 && !migrator.current_migration
    raise UnknownMigrationVersionError.new(current_version)
  end
  start_index =
    if current_version == 0
      0
    else
      migrator.migrations.index(migrator.current_migration)
    end
  finish = migrator.migrations[start_index + steps]
  version = finish ? finish.version : 0
  public_send(direction, version)
end