Create a shell auth.User.

def get_or_create_user(self, provider, access, info):
        "Create a shell auth.User."
        digest = hashlib.sha1(smart_bytes(access)).digest()
        # Base 64 encode to get below 30 characters
        # Removed padding characters
        username = force_text(base64.urlsafe_b64encode(digest)).replace('=', '')
        User = get_user_model()
        kwargs = {
            User.USERNAME_FIELD: username,
            'email': '',
            'password': None
        }
        return User.objects.create_user(**kwargs)