make the assignment review page visible to users who are members

and managers.
So couple of bits:

1. When I bootstrapped the pycon app, no reviewers group was created.
2. When I had a test user apply to be the reviewer they were never placed in the "reviewers" group and I am sure where it does so yet.

Just to note, so clearly it how it was done using the "team/membership" system since my code was borrowed from and there is no check there for the group https://github.com/pycon/pycon/blob/develop/symposion/reviews/views.py#L155