Fix total due amount in example user

Change-Id: I505ce53fedcfbc81167dee0b0c49471342614358
diff --git a/invoice.php b/invoice.php
index 6bcec79..6c2f57b 100644
--- a/invoice.php
+++ b/invoice.php
@@ -106,7 +106,7 @@
 $user->zip = "12345";
 $user->city = "Mannheim";
 $user->country = "Germany";
-$user->total_due = 260.0;
+$user->total_due = 285.0;
 $user->student = true;
 $user->lunch_day_1 = "vegan";
 $user->lunch_day_2 = "non-vegetarian";