Move Issuebot over

[maryolivier]

Background

Issuebot lives in slack-agile now. We want to move it over here so its maintained with everything else. We should probably do this after #174, so we dont have to go back and change this functionality to use a Slack App.

To do this, we will need to do a few things:

• Add the ability to associate a Slack Channel with a Github Repo. We should be able to associate multiple Github Repos to a Slack Channel and vice versa. In slack agile we had an interface to do this, but it would make sense to make a slash command for this action instead, given the nature of this project.
• Add an endpoint that the Events API can hit to trigger issuebot
• Add Issuebot functionality
  • We can make the issue bot respond with more information than it did before, but let's start with the basic link and name of the issue
  • Responds to non threaded messages that have one or multiple issues referenced
  • Responds to threaded messages that have one or multiple issues referenced
  • Does not respond to the whitelisted bot users, namely itself