diff --git a/mhackspace/users/migrations/0011_auto_20181011_0752.py b/mhackspace/users/migrations/0011_auto_20181011_0752.py
index 2650507..69cae8d 100644
--- a/mhackspace/users/migrations/0011_auto_20181011_0752.py
+++ b/mhackspace/users/migrations/0011_auto_20181011_0752.py
@@ -19,6 +19,6 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name='membership',
             name='payment_date',
-            field=models.DateTimeField(default=None),
+            field=models.DateTimeField(null=True),
         ),
     ]