Add basic testing for the Request model.
Add basic testing for the Request model.

Tests include all validations and associations, but model methods have
not yet been tested. This will be included in future releases.

nyc-mud-turtles-2015/nghborly,nyc-mud-turtles-2015/nghborly,kimchanyoung/nghborly,kimchanyoung/nghborly,nyc-mud-turtles-2015/nghborly,kimchanyoung/nghborly