reversible migrations.

src/documents/migrations/1000_update_paperless_all.py

@@ -1,4 +1,6 @@
 # Generated by Django 3.1.3 on 2020-11-07 12:35
+import uuid
+
 from django.db import migrations, models
 import django.db.models.deletion
 
@@ -20,6 +22,14 @@ def make_index(apps, schema_editor):
         print("  --> Cannot create document index.")
 
 
+def logs_set_default_group(apps, schema_editor):
+    Log = apps.get_model('documents', 'Log')
+    for log in Log.objects.all():
+        if log.group is None:
+            log.group = uuid.uuid4()
+            log.save()
+
+
 class Migration(migrations.Migration):
 
     dependencies = [
@@ -85,6 +95,10 @@ class Migration(migrations.Migration):
             name='group',
             field=models.UUIDField(blank=True, null=True),
         ),
+        migrations.RunPython(
+            code=django.db.migrations.operations.special.RunPython.noop,
+            reverse_code=logs_set_default_group
+        ),
         migrations.RunPython(
             code=make_index,
             reverse_code=django.db.migrations.operations.special.RunPython.noop,