Adding a Model Reference to existing Rails model

Question

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\

Answer 1

After you set belongs_to in Rabbit, and has_many in Clown, you can do a migration with:

add_column :rabbit, :clown_id, :integer

EDIT: See Paulo's answer below for a more updated answer (Rails 4+)