Setup Code Climate

Code Climate is a quality analysis tool. It's free for open source, so we might as well take advantage of it. It's actually been monitoring this repo for a couple of weeks, but these changes will have it monitor test coverage as well. I don't think the coverage reports will kick in until this goes into master, so I'll be merging soon. If you have feedback, make it quick!

https://codeclimate.com/github/ResourceDataInc/commuter_challenge