core: add migration to fix null fields in core.application

passbook/core/migrations/0011_auto_20200222_1822.py

@@ -0,0 +1,27 @@
+# Generated by Django 3.0.3 on 2020-02-22 18:22
+
+from django.db import migrations
+
+
+def fix_application_null(apps, schema_editor):
+    """Fix Application meta_fields being null"""
+    Application = apps.get_model("passbook_core", "Application")
+    for app in Application.objects.all():
+        if app.meta_launch_url is None:
+            app.meta_launch_url = ""
+        if app.meta_icon_url is None:
+            app.meta_icon_url = ""
+        if app.meta_description is None:
+            app.meta_description = ""
+        if app.meta_publisher is None:
+            app.meta_publisher = ""
+        app.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("passbook_core", "0010_auto_20200221_2208"),
+    ]
+
+    operations = [migrations.RunPython(fix_application_null)]