Second Pull Request - Project Course (ThreadBoard)

I am using the method `getByThreadId` po to both access the `comment` and `thread` table. Through that method, I'm getting the `body` of the comment "by thread id" as well as the `title` of the thread. That's why po  I need that method to be in the comment model. I happen to have errors po whenever I move it to the thread model :frowning: