Add missing migration

aleksis/apps/stoelindeling/migrations/0004_alter_seatingplan_subject.py

+# Generated by Django 3.2.12 on 2022-04-06 17:54
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('chronos', '0011_alter_timeperiod_weekday'),
+        ('stoelindeling', '0003_seat_negative_x_y'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='seatingplan',
+            name='subject',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='chronos.subject', verbose_name='Subject'),
+        ),
+    ]