Create migration file after change in .inviter

This is required because of the change introduced in this commit:

4235da2

Also, create a test to ensure that future commits don't forget to create
any necessary migration files.

invitations/migrations/0005_alter_invitation_inviter.py

@@ -0,0 +1,29 @@
+# Generated by Django 4.2.13 on 2024-06-13 12:44
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ("invitations", "0004_auto_20230328_1430"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="invitation",
+            name="inviter",
+            field=models.ForeignKey(
+                blank=True,
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="%(app_label)s_%(class)ss",
+                related_query_name="%(app_label)s_%(class)s",
+                to=settings.AUTH_USER_MODEL,
+                verbose_name="inviter",
+            ),
+        ),
+    ]

tests/test_migrations.py

@@ -0,0 +1,13 @@
+import pytest
+from django.core.management import call_command
+
+
+class TestMigrations:
+    @pytest.mark.django_db
+    def test_all_necessary_migrations_created(self):
+        try:
+            call_command("makemigrations", "--check", "--dry-run")
+            all_necessary_migrations_created = True
+        except SystemExit:
+            all_necessary_migrations_created = False
+        assert all_necessary_migrations_created