Setup integration with Badgr

[ryzokuken]

https://github.com/nodejs/badges has been set up to spearhead the node badges initiative.

In order to automate the process of issuing badges, I had been thinking about spinning up a service that would register webhooks using the GitHub API to automatically issue badges when certain conditions are met (first-time contribution, etc).

The conversation took place in https://github.com/nodejs/badges/issues/9 and I was instructed to get in contact with the team here in order to make it happen.

I'd need your help with the bare basics (if we go ahead and implement it as a function within the existing codebase for the bot). Any further assistance would also be appreciated.

[phillipj]

For future ref, @amiller-gh did a great job describing the overall concept of how the bot is tied together: https://github.com/nodejs/badges/issues/9#issuecomment-372146979.

If you've got any questions around specific parts, don't hesitate to ping me directly. I'm sure there's lots of improvements that could be made to make the bot easier to reason about, so please share your thoughts and experiences as you go along.