Require authentication for the user page
Show username on the profile page
A note on MVC
Pass template context to all views
Do not show the login form for authenticated users
Provide the full user info to the rendering context
Display an error message if user fails to log in
Mention the login page in README
Adding new tastings requires logging in
Editing coffees and roasteries is only allowed to admins
Ylläpitäjä -> Yllapitaja

Logging in does not work with ä in the username. I can't be bothered to
figure it out right now.
A small refactoring
Describe MVC in the docs