I wrote this as a proof of concept, mostly because I felt that
https://github.com/gavinwahl/django-u2f was too confusing to follow and
included a monkey patch.

The authentication system is not according to best practice, according to
Django two-factor standards. Additionally, Django has a two-factor application
that has U2F functionality below:
https://github.com/Bouke/django-two-factor-auth

You will need to create a new user with:
./manage.py createsuperuser

When you first login, you will be redirected to add_key(), to add a single new
U2F key. The second time you attempt to login will require you to login with
your U2F key.

If you find this confusing or hard to follow, feel free to drop me a line!
khanzf@gmail.com