I\'d like to know the \"proper\" way to approach adding a relation between two existing classes in Rails 3.
Given existing models: Clown & Rabbit
I\
I'm not sure where you got this idea, but there is no (and never has been) such syntax to do what you want with add_column. To get the behavior you want, you'd have to do t.refences :clown, as you stated. In the background this will call: @base.add_column(@table_name, "#{col}_id", :integer, options).
See here.
EDIT:
I think I can see the source of your confusion. You saw the method call t.reference and assumed it was a datatype because calls such as t.integer and t.string exist, and those are datatypes. That's wrong. Reference isn't a datatype, it's just simply the name of a method, similar to t.rename is.