Store User Names from Github

* Will improve intercom data, ie. allow us to address by name
* Includes a one off rake task for backfilling exisiting user's names
Good question, I was doing it to avoid the rate limit as its a super simple scrape. Open to doing it with a traditional api request as well. I was thinking it would be nice to get them all in a single go / not impact hound's normal # of requests.