code: func (builder *Dockerfile) installScripts(scriptsURL string, config *api.Config) []api.InstallResult {
  	scriptInstaller := scripts.NewInstaller(
  		"",
  		scriptsURL,
  		config.ScriptDownloadProxyConfig,
  		nil,
  		api.AuthConfig{},
  		builder.fs,
  	)
  
  	// all scripts are optional, we trust the image contains scripts if we don't find them
  	// in the source repo.
  	return scriptInstaller.InstallOptional(append(scripts.RequiredScripts, scripts.OptionalScripts...), config.WorkingDir)
  }
docs: // installScripts installs scripts at the provided URL to the Dockerfile context