code: func startGulp(publicPathEnv string, ctx context.Context) error {
  	_, err := os.Stat(filepath.Join(cnf.AppPath, "gulpfile.js"))
  	if os.IsNotExist(err) {
  		fmt.Println("No gulpfile.js present, skipping gulp watch")
  		return nil
  	} else if err != nil {
  		return err
  	}
  
  	_, err = exec.LookPath("gulp")
  	if err != nil {
  		fmt.Println("Cannot find gulp in PATH. Is it installed?")
  		return nil
  	}
  
  	cmd := exec.Command("gulp", "watch")
  
  	cmd.Stdin = os.Stdin
  	cmd.Stderr = os.Stderr
  	cmd.Stdout = os.Stdout
  	cmd.Env = append([]string{publicPathEnv}, os.Environ()...)
  
  	return cmd.Run()
  }
docs: // startGulp starts "gulp watch" if it can find gulpfile.js and the gulp command.