added missing migration

lab/experiments/migrations/0015_timeslot_end_after_start.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.11 on 2024-10-01 13:18
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("experiments", "0014_remove_experiment_additional_instructions"),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name="timeslot",
+            constraint=models.CheckConstraint(check=models.Q(("end__gt", models.F("start"))), name="end_after_start"),
+        ),
+    ]