#35 Weekend/Evening restrictions

[Trevor Riedemann]

Add the ability to limit users to specific periods of time for
scheduling. For example, flag the users who do/don’t have
the privilege of making weekend sign-ups, or after 5 PM.

We have SEM and TEM equipment were only certain well
qualified users are allowed to operate the equipment after
5PM or on the weekends. On the other hand our XRD is
24/7 for all users.