web/handlers.go
func SingleFile(filename string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filename)
	})
}
func SingleFile(filename string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filename)
	})
}
//SingleFile returns a handler