Need CommentBot tests

[zot]

We should add some tests for CommentBot. These should activate the full flow from browser -> GitHub -> web hook. It's possible there is a way to do this without @mock:

• use a test GitHub repo
• run a mock GitHub server during the test (change the url in the GitForge struct)
• Hit GitHub live and use a webhook multiplexing service
  • zapier
  • IFTTT
• use a mock GitForge forge

If @mock is the best way to do this, we can add mock calls to the registrator code.

@nkottary