code: func CreateSignupLink(client auth.ClientI, token string) (string, string) {
  	proxyHost := "<proxyhost>:3080"
  
  	proxies, err := client.GetProxies()
  	if err != nil {
  		log.Errorf("Unable to retrieve proxy list: %v", err)
  	}
  
  	if len(proxies) > 0 {
  		proxyHost = proxies[0].GetPublicAddr()
  		if proxyHost == "" {
  			proxyHost = fmt.Sprintf("%v:%v", proxies[0].GetHostname(), defaults.HTTPListenPort)
  			log.Debugf("public_address not set for proxy, returning proxyHost: %q", proxyHost)
  		}
  	}
  
  	u := &url.URL{
  		Scheme: "https",
  		Host:   proxyHost,
  		Path:   "web/newuser/" + token,
  	}
  	return u.String(), proxyHost
  }
docs: // CreateSignupLink generates and returns a URL which is given to a new
  // user to complete registration with Teleport via Web UI