Add mongodb support to gutterball

Testing is still a bit of a PITA at the moment, and require a live DB -- ugh. Played with Fongo, but there are some features of the mongodb-java-driver that are not currently supported.

TODO: Find a way to isolate these tests as integration tests.

NOTE: Some tests currently require a mongodb setup in order for them to be run.
This is precisely why I want to re-introduce ConfigProperties.java. These are constants that would've been defined in there and we would've defined them in the DEFAULT_PROPERTIES.