def set_to_redis
    $redis.mapped_hmset( redis_key, self.attributes )
  end

  def destroy_in_redis
    $redis.del redis_key
  end

  def self.find_in_redis(id)
    if $redis.hgetall "Post:#{id}".nil?
      post = Post.find(id)
      $redis.mapped_hmset( "Post:#{id}", post.attributes )
      $redis.hgetall "Post:#{id}"
    else
      $redis.hgetall "Post:#{id}"
    end
    ##WORK BUT will be rewrite !!! MPORTANT
  end