diff --git a/app/models/unidom/visitor/application_record.rb b/app/models/unidom/visitor/application_record.rb
index <HASH>..<HASH> 100644
--- a/app/models/unidom/visitor/application_record.rb
+++ b/app/models/unidom/visitor/application_record.rb
@@ -1,3 +1,6 @@
+##
+# Application record 是模块内所有模型的抽象基类。
+
 class Unidom::Visitor::ApplicationRecord < ActiveRecord::Base
   self.abstract_class = true
 end
1, Improve the Application record for the document.