.

longs/migrations/0031_auto_20210309_1527.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.1.3 on 2021-03-09 15:27
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('longs', '0030_long_recreate_json'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='exam',
+            name='json_creation_time',
+            field=models.DateTimeField(blank=True, default=None, null=True),
+        ),
+        migrations.AddField(
+            model_name='long',
+            name='json_creation_time',
+            field=models.DateTimeField(blank=True, default=None, null=True),
+        ),
+    ]

longs/models.py

@@ -120,7 +120,7 @@ class Long(models.Model):
         help_text="If the json cache needs updating", default=False
     )
 
-    json_creation_time = models.DateTimeField(blank=True)
+    json_creation_time = models.DateTimeField(blank=True, default=None, null=True)
 
     #question_file = models.FileField(upload_to=question_file_directory_path, blank=True, null=True)