Allow id to be string to support not integer ids (postgresql uuid)

[galetahub]

Record identifier type can be anything else, so it's better to use String type

[dskecse]

@galetahub for your specific case you could simply add a BaseForm to your app:

class BaseForm < Rectify::Form
  def persisted?
    id.present?
  end
end

and then derive your actual forms off of it.