update readme.md for clearer example
edited for correct routes.
updated readme to include Authentication example
missed the return statement on show method
exhibited User relationship from ApiKey model
updated for consistency in example
stateless authentication ;)
Merge pull request #8 from awkwardusername/patch-1

update readme.md for clearer example
Switch to PSR-4
Merge branch 'develop'

* develop:
  Switch to PSR-4