Uninitialized constant ActiveRecord::Singleton

I need to define a singleton ActiveRecord model. I do this:

class Universe < ActiveRecord::Base
  include ActiveRecord::Singleton

end

But I receive an error: uninitialized constant ActiveRecord开发者_如何学JAVA::Singleton. I assume, I missed require "something". What should I require?

I searched through the Rails documentation for 3.03 and I don't see any reference to ActiveRecord::Singleton. Are you absolutely sure this is a valid name?

I did find a reference to this library that appears to add this functionality though. Are you using this library?

Are you sure you are actually looking for ActiveRecord::Singleton? There is a Singleton-Module in the rails-standard-library:

http://www.ruby-doc.org/stdlib-1.9.3/libdoc/singleton/rdoc/Singleton.html

maybe this is what you are looking for?!