wcs: add migration for category filter (#17202)

combo/apps/wcs/migrations/0015_wcscurrentformscell_categories.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.8 on 2018-01-21 12:50
+from __future__ import unicode_literals
+
+from django.db import migrations
+import jsonfield.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wcs', '0014_auto_20170214_2006'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='wcscurrentformscell',
+            name='categories',
+            field=jsonfield.fields.JSONField(blank=True, default=dict),
+        ),
+    ]