Added seller interface for preparing shop items from other plugins.

commodity/commodityservice.cpp

@@ -35,3 +35,8 @@ ShopItemPtr CommodityService::shopItem(int itemId)
     CommodityDataPtr item = this->loadById(itemId);
     return qSharedPointerDynamicCast<ShopItem, CommodityData>(item);
 }
+
+ISeller *CommodityService::seller()
+{
+    return NULL;
+}

commodity/commodityservice.h

@@ -15,7 +15,7 @@ public:
     QList<ShopItemPtr> shopItems() override;
     void addedToVoucher(int itemId, int countAdded) override;
     virtual ShopItemPtr shopItem(int itemId) override;
-
+    ISeller *seller() override;
 };
 
 #endif // COMMODITYSERVICE_H