Adding configuration for HoundCI

In order to prevent any future conflicts (due to whitespace) when merging, this service will create comments pointing out any sloppy whitespace introduction.

It will allow [HoundCI](https://houndci.com/) to run [Rubocop](https://github.com/bbatsov/rubocop) and [Coffeelint](http://www.coffeelint.org/) on any new code introduced by the pull requests.