code: func (n *Negroni) With(handlers ...Handler) *Negroni {
  	currentHandlers := make([]Handler, len(n.handlers))
  	copy(currentHandlers, n.handlers)
  	return New(
  		append(currentHandlers, handlers...)...,
  	)
  }
docs: // With returns a new Negroni instance that is a combination of the negroni
  // receiver's handlers and the provided handlers.