@FXML
    public void addProductToOrder(){

        String nameOfProduct=selectedProduct.getSelectionModel().getSelectedItem().getName();
        String count = countOfProduct.getText();
        int amountOfProduct = Integer.parseInt(count);
        double priceOfProduct =selectedProduct.getSelectionModel().getSelectedItem().getPrice();
        Product product = new Product(nameOfProduct,amountOfProduct,priceOfProduct);

        if(DataBase.getInstance().reduceProductAmountIfPossible(selectedProduct.getSelectionModel().getSelectedItem(),amountOfProduct)){
            tableViewOrder.getItems().add(product);
        }
        else{

            Alert alert = new Alert(Alert.AlertType.ERROR);
            alert.setHeaderText("Nie mamy tyle towaru");
            alert.showAndWait();
        }
        costOfOrder.setText(sumOfOrder()+ " zł");

    }