Set one payment method as primary, allow updates

uncloud_django_based/uncloud/uncloud_pay/migrations/0003_auto_20200305_1354.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.0.3 on 2020-03-05 13:54
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('uncloud_pay', '0002_auto_20200305_1524.py'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='paymentmethod',
+            name='primary',
+            field=models.BooleanField(default=False, editable=False),
+        ),
+    ]