allow tasks with workflow null

atdb/taskdatabase/migrations/0025_auto_20230509_1631.py

+# Generated by Django 3.1.4 on 2023-05-09 14:31
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('taskdatabase', '0024_auto_20230509_1612'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='task',
+            name='workflow',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='tasks', to='taskdatabase.workflow'),
+        ),
+    ]