Added identifier and fetch time product listings; Added persistence to AdafruitShop.

Implemented in AdafruitShop.

AdafruitShop Product listing data now persisted.

AdafruitShop configuration now persisted.

Props/Extensions/ProductListingExtensions.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Builder;
 using Props.Shop.Framework;
 
 namespace Props.Extensions
@@ -10,5 +11,7 @@ namespace Props.Extensions
             int purchaseFactor = productListing.PurchaseCount.HasValue ? productListing.PurchaseCount.Value : 1;
             return (productListing.Rating * (reviewFactor > purchaseFactor ? reviewFactor : purchaseFactor)) / (productListing.LowerPrice * productListing.UpperPrice);
         }
+
+
     }
 }