public ActionResult AddMember(AddMembershipFormViewModel viewModel)
        {
            if (!ModelState.IsValid)
            {
                return(View("AddMember", viewModel));
            }

            var userId         = User.Identity.GetUserId();
            var newMember      = _context.Users.Single(u => u.Email == viewModel.Email);
            var organizationId = viewModel.OrganizationId;


            if (!_context.Memberships.Any(m => m.MemberId == newMember.Id && m.OrganizationId == organizationId) && _context.Organizations.Find(organizationId).OwnerId == userId)
            {
                var membership = new Membership()
                {
                    OrganizationId = organizationId,
                    MemberId       = newMember.Id
                };

                if (newMember.DefaultOrganizationId == null)
                {
                    newMember.DefaultOrganizationId = organizationId;
                }
                _context.Memberships.Add(membership);
                _context.SaveChanges();
            }



            return(RedirectToAction("Details", new { id = organizationId }));
        }
        public ActionResult AddMember(int id)
        {
            var viewModel = new AddMembershipFormViewModel()
            {
                OrganizationId = id
            };

            return(View(viewModel));
        }