resolve naive datetime warnings
diff --git a/planetstack/cassandra/migrations/0001_initial.py b/planetstack/cassandra/migrations/0001_initial.py
index 358c5dc..370e245 100644
--- a/planetstack/cassandra/migrations/0001_initial.py
+++ b/planetstack/cassandra/migrations/0001_initial.py
@@ -2,6 +2,7 @@
 from __future__ import unicode_literals
 
 from django.db import models, migrations
+import django.utils.timezone
 
 
 class Migration(migrations.Migration):