Multilevel Class inheritance

Hello there,

I am having a problem inheriting an already inherited class.

errr.. sounds more complicated than it is.. look:

class Item < ActiveRecord::Base # has a name and description field end

class Reference < Item # has a something field end

class UrlReference < Reference #has an url field end

... now If I do make a u = UrlReference.new in the console for example, the u instance does NOT have the url field.. only the ones from Reference and Item...

How come? I guess that's basic ruby.. but how do I properly inherit from other classes which again inherit from other ones? Did I miss something here?

Cheers & thanks, -Joerg