Increases/decreases custom counters when taggings are created/destroyed

config/initializers/acts_as_taggable_on.rb

@@ -1,8 +1,24 @@
 ActsAsTaggableOn::Tagging.class_eval do
-  after_destroy :touch_taggable
+  after_create :increase_custom_counter
+  after_destroy :touch_taggable, :decrease_custom_counter
 
   def touch_taggable
     taggable.touch if taggable.present?
   end
 
-end
+  def increase_custom_counter
+    ActsAsTaggableOn::Tag.increment_counter(custom_counter_field_name, tag_id)
+  end
+
+  def decrease_custom_counter
+    ActsAsTaggableOn::Tag.decrement_counter(custom_counter_field_name, tag_id)
+  end
+
+  private
+
+  def custom_counter_field_name
+    "#{self.taggable_type.underscore.pluralize}_count"
+  end
+
+
+end