public async Task <IActionResult> Edit(int id, [Bind("id,Name,GroupId")] GroupMember groupMember)
        {
            if (id != groupMember.id)
            {
                return(NotFound());
            }

            if (ModelState.IsValid)
            {
                try
                {
                    await _groupMember.UpdateGroupMember(groupMember);
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!GroupMemberExists(groupMember.id))
                    {
                        return(NotFound());
                    }
                    else
                    {
                        throw;
                    }
                }
                return(RedirectToAction(nameof(Index)));
            }
            ViewData["GroupId"] = new SelectList(_context.Groups, "id", "Name", groupMember.GroupId);
            return(View(groupMember));
        }