// GET: VacationReplacementRequests
        public ActionResult Index()
        {
            // identify logged-in user
            String currentUserId = User.Identity.GetUserId();

            DBQuery dbq = new DBQuery();
            var ReplacementReqList = new List<GUIManagement.VacationReplacementRequestViewItem>();

            String shiftPartnerID = dbq.SelectShiftPartner(currentUserId);

            if (shiftPartnerID != null)
            {
                var VRList = dbq.SelectSubmittedVacationRequestsOfShiftPartner(shiftPartnerID);
                String name = dbq.SelectEmployeeFullName(shiftPartnerID);

                foreach (VacationManagement.VacationRequest vr in VRList)
                {
                    GUIManagement.VacationReplacementRequestViewItem vrr = new GUIManagement.VacationReplacementRequestViewItem(vr, name);
                    ReplacementReqList.Add(vrr);
                }
            }
            else
            {
                // Labelausgabe GUI

            }
            return View(ReplacementReqList);
        }