Наличие «распределителя undefined для данных» при сохранении с Activeresource

Что мне не хватает? Я пытаюсь использовать службу отдыха с активным ресурсом, у меня есть следующее:

class User < ActiveResource::Base
  self.site = "http://localhost:3000/"
  self.element_name = "users"
  self.format = :json
end

user = User.new(
        :name => "Test",
        :email => "test.user@domain.com")

p user 
if user.save
  puts "success: #{user.uuid}"
else
  puts "error: #{user.errors.full_messages.to_sentence}"
end

и следующий вывод для пользователя:

#<User:0x1011a2d20 @prefix_options={}, @attributes={"name"=>"Test", "email"=>"test.user@domain.com"}>

и эта ошибка:

/Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1233:in `new': allocator undefined for Data (TypeError)
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1233:in `load'
from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1219:in `each'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1219:in `load'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1322:in `load_attributes_from_response'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1316:in `create_without_notifications'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1314:in `tap'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1314:in `create_without_notifications'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/observing.rb:11:in `create'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/base.rb:1117:in `save_without_validation'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/validations.rb:87:in `save_without_notifications'
    from /Library/Ruby/Gems/1.8/gems/activeresource-3.0.10/lib/active_resource/observing.rb:11:in `save'
    from import_rest.rb:22

, если я пользователю завивьте для моего Служба отдыха было бы похоже на:

curl -v -X POST -H 'Content-Type: application/json' -d '{"name":"test curl", "email":"test@gmail.com"}' http://localhost:3000/users

с ответом:

{"email":"test@gmail.com","name":"test curl","admin":false,"uuid":"afb8c98b-562a-4603-bbe4-f8f0816cef0d","creation_limit":5}