[https://trello.com/c/V1q0dzpL/13-1-5-create-badges-admin] Create badge engine

* Adds specs for badge model
* Adds shoulda-matchers to spec_helper
[https://trello.com/c/V1q0dzpL/13-1-5-create-badges-admin] Create admin badges

* Adds unique validation to badge model
* Adds unique index to badge's name
[https://trello.com/c/V1q0dzpL/13-1-5-create-badges-admin] Create admin badges

* Adds specs for badge model
* Adds specs for badge controller
* Adds libraries to spec helper