Thoughts on adding a value transform option or a 'type' option to Attribute?

[weilandia]

Specifically, I'd like to easily be able to send all id values to the client as strings without having to call to_s on every id attribute and without changing the Rails default of making ids integers.

So, instead of

attribute :contract_id do |obj|
  obj.contract_id.to_s
end

Something like

attribute :contract_id, type: :string

or

attribute :contract_id, coerce: :string