code: func (p *Provider) Append(systemRouter *mux.Router) {
  	systemRouter.
  		Methods(http.MethodPut).
  		Path("/api/providers/{provider}").
  		HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
  
  			vars := mux.Vars(request)
  			if vars["provider"] != "rest" {
  				response.WriteHeader(http.StatusBadRequest)
  				fmt.Fprint(response, "Only 'rest' provider can be updated through the REST API")
  				return
  			}
  
  			configuration := new(config.HTTPConfiguration)
  			body, _ := ioutil.ReadAll(request.Body)
  
  			if err := json.Unmarshal(body, configuration); err != nil {
  				log.WithoutContext().Errorf("Error parsing configuration %+v", err)
  				http.Error(response, fmt.Sprintf("%+v", err), http.StatusBadRequest)
  				return
  			}
  
  			p.configurationChan <- config.Message{ProviderName: "rest", Configuration: &config.Configuration{
  				HTTP: configuration,
  			}}
  			if err := templatesRenderer.JSON(response, http.StatusOK, configuration); err != nil {
  				log.WithoutContext().Error(err)
  			}
  		})
  }
docs: // Append add rest provider routes on a router.