added more gateway enums

src/Core/Enums/GatewayType.cs

@@ -3,6 +3,9 @@
     public enum GatewayType : byte
     {
         Stripe = 0,
-        Braintree = 1
+        Braintree = 1,
+        AppStore = 2,
+        PlayStore = 3,
+        Coinbase = 4
     }
 }