Revert "DonĀ“t display VAT for City Walk"

This reverts commit 1f64cdd6c362e9f80680a10834caf244e4d8eb82.
diff --git a/invoice.php b/invoice.php
index 94b85a8..5ca3e34 100644
--- a/invoice.php
+++ b/invoice.php
@@ -78,9 +78,8 @@
     if ($user->excursion) {
         $net = $EXCURSION / (1 + $FULL_VAT);
         $vat = $EXCURSION - $net;
-        # $vat_sum += $vat;
-        # $invoice->addItem('Guided City Walk', 'The Guided City Walk takes place in the late afternoon of 21 July.', 1, false, $net, $vat, $EXCURSION);
-        $invoice->addItem('Guided City Walk', 'The Guided City Walk takes place in the late afternoon of 21 July.', 1, false, $EXCURSION, "", $EXCURSION);
+        $vat_sum += $vat;
+        $invoice->addItem('Guided City Walk', 'The Guided City Walk takes place in the late afternoon of 21 July.', 1, false, $net, $vat, $EXCURSION);
     }
 
     /* Add totals */