public IActionResult Remove(RemoveAddUserRoleViewModel model)
        {
            Enum.TryParse(model.Role, out Role role);
            var userRole = this._context.UserRoles.FirstOrDefault(ur => ur.UserId == model.UserId && ur.Role == role);

            if (userRole != null)
            {
                this._context.UserRoles.Remove(userRole);

                this._context.SaveChanges();
            }

            var redirect = "/manage/user-roles/" + model.UserId;

            return(RedirectPermanent(redirect));
        }
        public IActionResult Add(RemoveAddUserRoleViewModel model)
        {
            Enum.TryParse(model.Role, out Role role);
            var duplicate = this._context.UserRoles.FirstOrDefault(ur => ur.UserId == model.UserId && ur.Role == role);

            if (duplicate == null)
            {
                this._context.UserRoles.Add(new UserRole()
                {
                    Id     = Guid.NewGuid(),
                    UserId = model.UserId.Value,
                    Role   = role
                });

                this._context.SaveChanges();
            }

            var redirect = "/manage/user-roles/" + model.UserId;

            return(RedirectPermanent(redirect));
        }