Wiki model

Granted I'm still learning to think abstractly I wasn't entire sure if to make a Wiki model and a Comments model. I know we need a wiki (which is akin to posts) and a topics (or subject) like wikipedia. 

Now, wikipedia doesn't have community comments on the wikis. So i dont need that model, right? 

But for the cap project (heretofore, known as gitnotes for the sake of clarity) I would want users to comment. 

Thoughts?