Destroy user_attributes and attribute_values when a user is destroyed

app/models/user.rb

@@ -10,6 +10,7 @@ class User
   field :admin, :type => Boolean, :default => true
   field :active_roles, :type => Array
   
+  has_many :user_attributes
   has_many :user_roles
   has_many :user_infos
   before_save :clean_active_roles