Merge pull request #217 from observatorycontrolsystem/fix/timezone-aw…

…are-consistency

Maintain consistent use of timezone-aware datetimes

observation_portal/observations/tasks.py

@@ -1,6 +1,7 @@
 import dramatiq
 import logging
-from datetime import datetime, timedelta
+from datetime import timedelta
+from django.utils import timezone
 
 from observation_portal.observations.models import Observation
 
@@ -9,6 +10,6 @@
 
 @dramatiq.actor()
 def delete_old_observations():
-    cutoff = datetime.utcnow() - timedelta(days=14)
+    cutoff = timezone.now() - timedelta(days=14)
     logger.info(f'Deleting CANCELED observations before cutoff date {cutoff}')
     Observation.delete_old_observations(cutoff)