Notices are pages that admins can fill with their content to describe
and customize the room.
Pinned notices are common notices that each room has. Like a description
and privacy policy.
* update models
* simple crud test for basic notices
* edit and save notices as admin
This removes the nasty need for creating the database manually.
Migrations are kept in an embedded filesystem, just like the templates
and assets for the web frontend. The same -tags dev trick applies for
them.