Rails - Jan 2006 - Extending a model in a component...

I know I''m missing something basic, but I need help understanding  
something:

I have a model (User) sitting in a component.  I want to extend that  
model from my app.  I need to add in a has_many relationship and a  
couple of methods.

I was able to mixin the methods using this:

module MyUser
	def my_new_method
		# etc
	end
end

User.send(:include, MyUser::Acts::Chicken)

This just mixes in the new method.  But if I add a ''has_many'',
I get
an error.

I''ve tried using the way to extend ActiveRecord (like in a plugin),  
but that''s not working either.

module MyUser
       def self.append_features(base)
         super
         base.extend(ClassMethods)
       end

       module ClassMethods
         def my_new_method
         end
       end

end

User.send(:include, MyUser)


I''m not understanding the basics of extending a class, not just  
mixing things in.  Any pointers on this?

Thanks,
Brett