Create new Use Entity and associated migration.
Remove annotations from DashboardController.

There are so many blog articles describing why annotations in php are evil, and I decided to remove annotations entirely from the application.
Create new SecurityController, associated view, routing and test.
Fix bug in Entity User->getRoles() returning null instead of an array.
Provisionally fix issue causing the user to be de-authenticated.

I don't know if this is really fixed this way, 'cause this piece of code is un-documented, is it?
Use default code for security.

I'll customize the login form later ...