code: func (u *ResourceCommand) createUser(client auth.ClientI, raw services.UnknownResource) error {
  	user, err := services.GetUserMarshaler().UnmarshalUser(raw.Raw)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	userName := user.GetName()
  	if err := client.UpsertUser(user); err != nil {
  		return trace.Wrap(err)
  	}
  	fmt.Printf("user '%s' has been updated\n", userName)
  	return nil
  }
docs: // createUser implements 'tctl create user.yaml' command