Housekeeping - let's make all the Rev open source repos consistent!

[radditude]

There's still a few things left to do in order to make this repo an awesome place to contribute. Checklist as follows:

• [x] Readme
  • [x] Links to license
  • [x] Links to Hex page for package (check out shields.io to link it up the fancy way)
• [x] Is hooked up to a Slack channel somewhere so we get notified about issues/PRs
• [ ] Issue template (optional but encouraged) - http://wiki.revelry.co/index.php/Open_Source_Issue_Template