Add migration.

biscuit/core/migrations/0004_otp_yubikey.py

+from django.db import migrations
+
+from otp_yubikey.models import ValidationService
+
+def create_validation_service(apps, schema_editor):
+    ValidationService.objects.create(
+        name='default', use_ssl=True
+    )
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0003_school_logo'),
+    ]
+
+    operations = [
+        migrations.RunPython(create_validation_service),
+    ]