Upgrade Django major (#144)

* Bump dependency versions

* Configure default auto field implementation

* fix admin to use token proxy model

* update django docs link

siteroot/settings/base.py

@@ -73,6 +73,8 @@ TEMPLATES = [
     },
 ]
 
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'
+
 WSGI_APPLICATION = 'siteroot.wsgi.application'
 
 # Database