allow the dev to log in as any user, always in admin group
    
    Allowing the developer to log in as any user is important to work on web UI
    which shows the "Review" column differently, if you're logged in as a user who
    already voted.
    
    Always placing the user into the admin group is a quality of life improvement.
    The default config is created with FAS_ADMIN_GROUP='', which prevents any admin
    access until you correctly populate it (with "qa-admin"). That serves little
    purpose. Instead, assign the admin group to the FakeFAS user automatically,
    whichever its value is (even an empty string).