diff --git a/app/models/tag.rb b/app/models/tag.rb
index 9fb6b31..5bd86d4 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -1,4 +1,7 @@
 class Tag < ActiveRecord::Base
+  has_many :taggings,
+    :dependent => :delete_all
+
   attr_accessor :filtered_count
 
   scope :accessible_to, ->(user) do