added rpnNotify handler

main.go

@@ -11,6 +11,7 @@ func main() {
 
 	http.HandleFunc("/choosePayment", choosePayment)
 	http.HandleFunc("/rpnNameAndCard", rpnNameAndCard)
+	http.HandleFunc("/rpn_notify", rpnNotify) //called by rpn
 	// http.HandleFunc("/", Index)
 	// http.HandleFunc("/show", Show)
 	// http.HandleFunc("/new", New)