Google product categories for Google Shopping

The Application extends the file with product offer for Google Shopping (https://www.sote.pl/docs/google-shopping-integracja-z-google-merchant) and for Facebook (https://www.sote.pl/sklep-na-facebooku.html) with Google categories.
The Google product category [google_product_category] attribute is added to a Google Merchant file. The attribute indicates the category listed in Google category map that the product belongs to. Once a product is allocated to the proper category, respective ad will be displayed in response to relevant searches.