>> SPEAKER: The Chart function should display all of the passengers that are
in your shuttle and empty seat if empty.
So Chart should iterate over shuttle.seats, displaying the
passenger information for every index and empty seat if that index is null.
Now if HTML text is put inside of a JavaScript variable, then by using
document.getElementByID, Chart can edit the inner HTML of that given
element by assigning the HTML text to the
document.getElementByID inner HTML variable.