Simple association

gistfile1.rb

#app/model/user.rb
class User < ActiveRecord::Base
  #Du coup tu peux appeler @user.address => Objet Address instancie
  :has_one :address
end

#app/model/address.rb
class Address < ActiveRecord::Base
  #Du coup tu peux appeler @address.user => Objet User instancie
  :belongs_to :address
end