omniauth and user models (this is just for demo)

omniauth_user_models_demo.rb

#app/models/user.rb
class User < ActiveRecord::Base
  has_many :authorizations, :dependent => :destroy
end

#app/models/authorization.rb
class Authorization < ActiveRecord::Base
  belongs_to :user
  validates_presence_of :user_id, :uid, :provider
  validates_uniqueness_of :uid, :scope => :provider
end