Merge pull request encode#1997 from agconti/patch-1

docs(api-guide/authentication): updated to reflect new standards in Django 1.7

Author: xordoquy

docs/api-guide/authentication.md

@@ -168,12 +168,13 @@ The `curl` command line tool may be useful for testing token authenticated APIs.
 
 If you want every user to have an automatically generated Token, you can simply catch the User's `post_save` signal.
 
+    from django.conf import settings
     from django.contrib.auth import get_user_model
     from django.db.models.signals import post_save
     from django.dispatch import receiver
     from rest_framework.authtoken.models import Token
 
-    @receiver(post_save, sender=get_user_model())
+    @receiver(post_save, sender=settings.AUTH_USER_MODEL)
     def create_auth_token(sender, instance=None, created=False, **kwargs):
         if created:
             Token.objects.create(user=instance)