policies/expression: remove pb_flow_plan, save flow context directly in context

passbook/policies/expression/migrations/0002_auto_20200926_1156.py

@@ -0,0 +1,28 @@
+# Generated by Django 3.1.1 on 2020-09-26 11:56
+
+from django.apps.registry import Apps
+from django.db import migrations
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+
+
+def remove_pb_flow_plan(apps: Apps, schema_editor: BaseDatabaseSchemaEditor):
+    ExpressionPolicy = apps.get_model(
+        "passbook_policies_expression", "ExpressionPolicy"
+    )
+
+    db_alias = schema_editor.connection.alias
+
+    for policy in ExpressionPolicy.objects.using(db_alias).all():
+        policy.expression.replace("pb_flow_plan.", "context.")
+        policy.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("passbook_policies_expression", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.RunPython(remove_pb_flow_plan),
+    ]