// constructor
 public ManageController(UserManager <NoviArtUser> userManager, SignInManager <NoviArtUser> signInManager, ILogger <ManageController> logger, NoviArtDbContext dbcontext, IPaymentService paymentservice)
 {
     _userManager    = userManager;
     _signInManager  = signInManager;
     _logger         = logger;
     _dbcontext      = dbcontext;
     _paymentservice = paymentservice;
 }
        // constructor
        public HomeController(ILogger <HomeController> logger, NoviArtDbContext dbcontext, UserManager <NoviArtUser> userManager, IPaymentService paymentservice)
        {
            _logger         = logger;
            _dbcontext      = dbcontext;
            _userManager    = userManager;
            _paymentService = paymentservice;

            // verwerk vestreken huurperiodes voor ieder sessie, op de achtergrond
            new Action(async() => await ReleaseArtPiecesAsync())();
        }