chore: Add DEFAULT_AUTO_FIELD to settings.py

Author: jennifer-richards

ietf/settings.py

@@ -12,6 +12,8 @@
 import warnings
 from typing import Any, Dict, List, Tuple # pyflakes:ignore
 
+import django.db.models
+
 warnings.simplefilter("always", DeprecationWarning)
 warnings.filterwarnings("ignore", message="'urllib3\\[secure\\]' extra is deprecated")
 warnings.filterwarnings("ignore", message="The logout\\(\\) view is superseded by")
@@ -102,6 +104,11 @@
 
 USE_TZ = True
 
+# Default primary key field type to use for models that don’t have a field with primary_key=True.
+# In the future (relative to 4.2), the default will become 'django.db.models.BigAutoField.'
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'
+
+
 if SERVER_MODE == 'production':
     MEDIA_ROOT = '/a/www/www6s/lib/dt/media/'
     MEDIA_URL  = 'https://www.ietf.org/lib/dt/media/'