code: func (h *HTTPBin) RedirectTo(w http.ResponseWriter, r *http.Request) {
  	q := r.URL.Query()
  
  	url := q.Get("url")
  	if url == "" {
  		http.Error(w, "Missing URL", http.StatusBadRequest)
  		return
  	}
  
  	var err error
  	statusCode := http.StatusFound
  	rawStatusCode := q.Get("status_code")
  	if rawStatusCode != "" {
  		statusCode, err = strconv.Atoi(q.Get("status_code"))
  		if err != nil || statusCode < 300 || statusCode > 399 {
  			http.Error(w, "Invalid status code", http.StatusBadRequest)
  			return
  		}
  	}
  
  	w.Header().Set("Location", url)
  	w.WriteHeader(statusCode)
  }
docs: // RedirectTo responds with a redirect to a specific URL with an optional
  // status code, which defaults to 302