This change adds a simple new view that just lists all of the registered users

and links to the detail pages. This will make it possible to use the sonar UI

to set up new students to be in the right groups and have school/email/etc

data, instead of having to edit it in MongoDB directly.
Along with this, I've fixed it up so only mentors see the list of students in

the sidebar.

Looked at the new user list. Checked that both it and the sidebar linked to the

detail views.