def unlike(likeable)
    	if @@likeable_model_names.include? likeable.class.to_s.downcase
    		likeable.likers.delete self
    		self.save
    	else 
    		false
    	end
    end
def unlike(likeable)
    	if @@likeable_model_names.include? likeable.class.to_s.downcase
    		likeable.likers.delete self
    		self.save
    	else 
    		false
    	end
    end
user unlike a likeable

 example
 ===========

 	user.unlike(likeable)