Add example of a service and a parameter.
Add Doctrine and install 'script'.
Move code to an extended Application class.
Add Configuration service provider.
Create service provider.
Add Route Provider.
Add user creation and reading routes.
Move to service controllers and param converters.
Add age field for users.
Add PUT support.
Add message support.
Exception handling with error().
Use Hal for GET responses, including content negotiation.
Add caching and 304 support.