Rails 3 migrations: Adding reference column?
If you are using the Rails 4.x you can now generate migrations with references, like this:
rails generate migration AddUserRefToProducts user:referenceslike you can see on rails guides
EDIT: This is an outdated answer and should not be applied for Rails 4.x+
You don't need to add references when you can use an integer id to your referenced class.
I'd say the advantage of using references instead of a plain integer is that the model will be predefined with belongs_to and since the model is already created and will not be affected when you migrate something existing, the purpose is kind of lost.
So I would do like this instead:
rails g migration add_user_id_to_tester user_id:integerAnd then manually add belongs_to :user in the Tester model
Please note that you will most likely need an index on that column too.
class AddUserReferenceToTester < ActiveRecord::Migration def change add_column :testers, :user_id, :integer add_index :testers, :user_id endend