Added basic user authentication.

README.md

@@ -4,4 +4,8 @@ A basic pure HTML+CSS gallery viewer in the vein of [PiGallery 2](https://bpatri
 
 ## User authentication.
 
-Currently there is no authentication at all because I don't need it. This is meant to be installed in a server with HTTP basic auth enabled if needed.
+To login a user should be manually created by running the following commands in the Django shell, substituting the user's name, email and password as needed:
+
+    from django.contrib.auth.models import User
+    user = User.objects.create_user('<USERNAME>', '<EMAIL>', '<PASSWORD>')
+    user.save()