Who can create a group?

By default, Principals and Teachers are the only users able to create groups.  A group must always have a staff member as a moderator. When a teacher creates a group, the group is associated with (created under) the school they belong to. The teacher is able to add students they teach to the group and invite anybody in the school community to join the group. No one outside the school community can be invited to join the group or see the group.