Add new migration.

biscuit/apps/chronos/migrations/0003_lessonsubstitution_canceled.py → biscuit/apps/chronos/migrations/0003_auto_20190907_1419.py

-# Generated by Django 2.2.5 on 2019-09-07 13:24
+# Generated by Django 2.2.5 on 2019-09-07 14:19
 
 from django.db import migrations, models
 
@@ -12,7 +12,11 @@ class Migration(migrations.Migration):
     operations = [
         migrations.AddField(
             model_name='lessonsubstitution',
-            name='canceled',
+            name='cancelled',
             field=models.BooleanField(default=False),
         ),
+        migrations.AddConstraint(
+            model_name='lessonsubstitution',
+            constraint=models.CheckConstraint(check=models.Q(('cancelled', True), ('subject__isnull', False), _negated=True), name='either_substituted_or_cancelled'),
+        ),
     ]