class UserRole < ActiveRecord::Base
-
- ALL_ROLES = ['administrator', 'moderator']
-
- validates_inclusion_of :role, :in => ALL_ROLES
belongs_to :user
+ belongs_to :granter, :class_name => "User"
+
+ ALL_ROLES = %w(administrator moderator).freeze
+ validates :role, :inclusion => ALL_ROLES, :uniqueness => { :scope => :user_id }
end