code: func AddUsersToGroup(name string, members ...string) error {
  	if len(members) == 0 {
  		return fmt.Errorf("no members to add")
  	}
  	for i, v := range members {
  		if v == "" {
  			return EmptyMemberError(fmt.Sprintf("members[%s]", strconv.Itoa(i)))
  		}
  	}
  
  	// Group
  	gr, err := LookupGroup(name)
  	if err != nil {
  		return err
  	}
  	if err = _addMembers(&gr.UserList, members...); err != nil {
  		return err
  	}
  
  	// Shadow group
  	sg, err := LookupGShadow(name)
  	if err != nil {
  		return err
  	}
  	if err = _addMembers(&sg.UserList, members...); err != nil {
  		return err
  	}
  
  	// Editing
  	if err = edit(name, gr); err != nil {
  		return err
  	}
  	if err = edit(name, sg); err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // AddUsersToGroup adds the members to a group.