Authenticate

This is more a RFC, so don't just wack it in!

It is lacking a good error response when you try to access resources you don't have access to in the frontend, but that is easy to fix.

It is blocking the wordcloud if you don't authenticate. This is by design, and meant as an example.

The backend needs more work on the user management. It needs to store the user and maybe give it an id so we can use it for something useful!