taggable.rb

has_many :tags_taggings, :as => :taggable, :class_name => 'Tagging', :conditions => "taggings.association = 'tags'", :dependent => :destroy
  has_many :tags, :class_name => 'Tag', :through => :tags_taggings, :source => :tag
  
has_many :likes_taggings, :as => :taggable, :class_name => 'Tagging', :conditions => "taggings.association = 'likes'", :dependent => :destroy
  has_many :likes, :class_name => 'Tag', :through => :likes_taggings, :source => :tag


define_index do
  indexes tags(:name), :as => :tags
  indexes likes(:name), :as => :likes
end