permit blank payload in callbacks

src/shop/migrations/0040_auto_20170408_1055.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.5 on 2017-04-08 08:55
+from __future__ import unicode_literals
+
+import django.contrib.postgres.fields.jsonb
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('shop', '0039_auto_20170403_1752'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='epaycallback',
+            name='payload',
+            field=django.contrib.postgres.fields.jsonb.JSONField(blank=True),
+        ),
+    ]

src/shop/models.py

@@ -309,7 +309,7 @@ class EpayCallback(CreatedUpdatedModel, UUIDModel):
         verbose_name_plural = 'Epay Callbacks'
         ordering = ['-created']
 
-    payload = JSONField()
+    payload = JSONField(blank=True)
     md5valid = models.BooleanField(default=False)
 
     def __str__(self):