Auto assign username

apps/user/models.py

@@ -21,7 +21,7 @@ class UserManager(BaseUserManager):
 
     def _create_user(self, username, email, password, **extra_fields):
         if not username:
-            raise ValueError('The given username must be set')
+            username = email
         if not password:
             password = self.make_random_password()
         super().save(*args, **kwargs)