Summary

We need a way for project managers to add members to their project and assign them roles

Detailed Description

#693 introduces a backend for permissions & roles but these can currently only be assigned by superadmins in the Django admin.

#639 discusses some ideas of where to put project settings.

My suggestion is to keep this simple and add dedicated button & modal for managing project members. On the project detail view. But multiple paths to get there is a good idea.