Adding Wheelbarrow & Handcart Calculator

Hey,

Would be nice if you could add my calculator which calculates when it's better to research wheelbarrow/handcart, or when it's better to get 3/2.2 more vils (purely from an economy standpoint and in the long-term). The URL is here:

https://bstrasser53.github.io/WheelbarrowHandcartCalculator/

Cheers,

Bernhard