/**
* Create a new reply for the topic.
*
* @param array $values
* @param array $expected
* @return Model_Forum_Post
*/
public function create_reply(array $values, array $expected)
{
$post = new Model_Forum_Post();
$post->topic_id = $this->id;
$post->create_post($values, $expected);
// Set the last_post_id to the newly created post and increase replies.
$this->last_post_id = $post->id;
$this->replies++;
$this->save();
}
