Add tagged_ids to taggable

app/models/tagging.rb

@@ -6,4 +6,12 @@ class Tagging
 
   belongs_to :tag
   belongs_to :taggable, polymorphic: true
+
+  before_destroy :update_taggable_tag_ids
+
+  private
+
+  def update_taggable_tag_ids
+    self.taggable.remove_id(self.tag.id)
+  end
 end