sample txt of the ex15, not important, just for pull/fetch
Exercise 17: More Files "Ruby script to copy one file to another."
Ex17 extra credit:  make the  script shorter
Exercise 18: Names, Variables, Code, Functions "introducing function"
Exercise 19: Functions And Variables "variables in our
function are not connected to the variables in our script"
Ex 19 extra credit, 1 more function made  and run it 10 different ways
Exercise 20: Functions And Files "how functions and files can
work together"
Ex 20 extra credit, change to shorthand notation etc...