public async Task <IActionResult> UnregisterActivity(int id)
        {
            var signedUp = _allReadyDataAccess.GetActivitySignup(id, User.GetUserId());

            if (signedUp == null)
            {
                return(HttpNotFound());
            }
            await _allReadyDataAccess.DeleteActivitySignupAsync(signedUp.Id);

            return(new HttpStatusCodeResult((int)HttpStatusCode.OK));
        }