fix migration hierarchy after undoing the #21 revert (#21, #631) (#643)

peeringdb_server/migrations/0028_ixlan_remove_auto_increment.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.23 on 2020-01-02 09:24
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("peeringdb_server", "0027_never_via_route_servers"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="ixlan",
+            name="id",
+            field=models.IntegerField(primary_key=True, serialize=False),
+        ),
+    ]