Normalize supervisor emails and add unique constraint for case-insensitive email uniqueness

generic/migrations/0029_add_unique_constraint_supervisor_email.py

@@ -0,0 +1,17 @@
+from django.db import migrations
+from django.db.models import UniqueConstraint
+from django.db.models.functions import Lower
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('generic', '0028_normalize_supervisor_emails'),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name='supervisor',
+            constraint=UniqueConstraint(Lower('email'), name='unique_supervisor_email_ci'),
+        ),
+    ]