Change ModuleAppTag into "Module name"Tag.

vendor/built_in_modules/announcement/app/models/announcement_tag.rb

@@ -1,4 +1,4 @@
-class ModuleAppTag < Tag
+class AnnouncementTag < Tag
   
   has_and_belongs_to_many :bulletins
   

vendor/built_in_modules/announcement/app/models/bulletin.rb

@@ -8,7 +8,7 @@ class Bulletin
   has_one :title, :class_name => "I18nVariable", :as => :language_value, :autosave => true, :dependent => :destroy
   has_one :subtitle, :class_name => "I18nVariable", :as => :language_value, :autosave => true, :dependent => :destroy
   has_one :text, :class_name => "I18nVariable", :as => :language_value, :autosave => true, :dependent => :destroy
-  has_and_belongs_to_many :tags, :class_name => "ModuleAppTag"
+  has_and_belongs_to_many :tags, :class_name => "AnnouncementTag"
 
   field :postdate , :type => Date
   field :deadline , :type => Date