Set RACK_ENV='test' in rspec_helper
Coded "Use Invite" story.

Implemented the following tests:
* App "can use a new invite"
* App "cannot use an invite with an available_quantity of 0"

Implemented FactoryGirl to build the test objects.
built tests+code for 'Create an Invite' story
Added migration to make unique index for Invite
Added 'must have unique code' validation to spec
Implemented functionality for List Invites story

Built the get '/invites' route.
Implemented following tests:
* lists the available invites associated with the given API token
* not passed a valid api token / cannot list available invites