frontend: add robots.txt to disallow

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

src/frontend/main.go

@@ -119,6 +119,7 @@ func main() {
 	r.HandleFunc("/logout", svc.logoutHandler).Methods(http.MethodGet)
 	r.HandleFunc("/cart/checkout", svc.placeOrderHandler).Methods(http.MethodPost)
 	r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir("./static/"))))
+	r.HandleFunc("/robots.txt", func(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "User-agent: *\nDisallow: /") })
 
 	var handler http.Handler = r
 	handler = &logHandler{log: log, next: handler} // add logging