public function like($userId=null)
	{
		if(is_null($userId)) {
			$userId = $this->loggedInUserId();
		}
		
		if($userId) {
			$like = $this->likes()
				->where('user_id', '=', $userId)
				->first();
	
			if($like) return;
	
			$like = new Like();
			$like->user_id = $userId;
			$this->likes()->save($like);
		}

		$this->incrementLikeCount();
	}