Add instructions on running Rubocop and RSpec
Improve class1 laptop test instructions
Improve class3 exercises
Add a scratch pad
Fix bugs in class3 exercise3 specs (thanks Amanda)
Re-word instructions for class2 exercise 3
Remove class4 git_config
Fix exercise name
Tweak branching example
Improve class4 exercises
Tweak TIP
correct specs for exercise 1
correct specs