pull request

the quizzes have been a good way to show us what we don't know, which is amazing feedback.  from the last ruby quiz i wasn't able to build a class and test the methods in the class.  i improved from that and was able to work through two of the methods before the quiz ended.

first I built out all the tests and then approached the problem from making each method pass.  if you look at the big_diff method in the Quiz class i worked out my thought process first and then went into pry to mess with the array.  

this is a good step in the right direction.