Add tests to device_token_spec

Add tests for device_id (new and replace)
Add device_id to schema
Update create method in device_tokens_controller

Now checks to see if a matching device_id is present before creating a new device_token
Bump version
Remove extraneous device_id assignment
Merge pull request #35 from FutureWorkshops/add_device_id

Add device id to DeviceToken