Allow class_required to be empty

fai_webapi_djrf/migrations/0004_alter_packageconfig_class_required.py

+# Generated by Django 3.2.13 on 2022-05-27 19:49
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fai_webapi_djrf', '0003_scripts'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='packageconfig',
+            name='class_required',
+            field=models.ManyToManyField(blank=True, related_name='additional_for_package_configs', to='fai_webapi_djrf.Class'),
+        ),
+    ]

fai_webapi_djrf/models.py

@@ -428,7 +428,7 @@ class PackageConfig(models.Model):
         )
     )
     class_required = models.ManyToManyField(
-        "Class", related_name="additional_for_package_configs"
+        "Class", related_name="additional_for_package_configs", blank=True
     )
 
     def __str__(self):