Add initial Shopfoo pattern feature

data models, import/export, web views etc.

rattail_demo/importing/model.py

@@ -0,0 +1,18 @@
+# -*- coding: utf-8; -*-
+"""
+Rattail Demo model importers
+"""
+
+from rattail.importing.model import ToRattail
+from rattail_demo.db import model
+
+
+##############################
+# custom models
+##############################
+
+class ShopfooProductImporter(ToRattail):
+    """
+    Importer for ShopfooProduct data
+    """
+    model_class = model.ShopfooProduct