public async Task <IActionResult> DeleteInvite(Guid groupId)
        {
            // deletes entry from GroupInvites table
            string uid        = User.FindFirst(ClaimTypes.NameIdentifier).Value;
            var    tempInvite = await _context.GroupInvite.Where(x => x.GroupId == groupId && x.UserId == uid).ToListAsync();

            _context.Remove(tempInvite[0]);
            await _context.SaveChangesAsync();

            return(RedirectToAction("ListGroups"));
        }