add missing migration

src/wagtail_personalisation/migrations/0019_auto_20180526_1425.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.0.5 on 2018-05-26 14:25
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wagtail_personalisation', '0018_segment_excluded_users'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='personalisablepagemetadata',
+            name='segment',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='page_metadata', to='wagtail_personalisation.Segment'),
+        ),
+    ]