Added all the required dependencies for Spring Data.
Added the extra logging configuration for the new dependencies.
Created a new User class that will be persisted by Spring Data.
Created a new UserRepository that will be used to persist Users.
Configured Spring Data.
Added some User CRUD endpoints.
Overrode User.isNew() to tag it to be ignored by Jackson on serialisation.
Created User retrieve all and delete endpoints.
Updated the README.md to contain info about the new CRUD endpoints.