Use application's package as unique identifier

[tomkonidas]

We have decided to use the package instead of generating a uniq id. The package is always uniq.

We would now use the api as such:	Method	Route
GET	/api/v1/applications/:package
POST	/api/v1/applications
GET	/api/v1/applications/:package/ratings
GET	/api/v1/applications/:package/ratings/:id
POST	/api/v1/applications/:package/ratings

When submitting POST requests for a rating, you would now provide the application_package instead of the application_id.

Screenshots:

Get an application

Get an application's ratings

Get an application's particular rating

Create an application

Rate an application