Fix to class 7 exercise 1
Add exercises for class 8
Add class guidelines
Tweaks fish colors
Improve the Change PATH globally section
Improve sublime text instructions
Tweak sublime text instructions
Improve chruby and ruby-install instructions
Fix typo
Fix ruby-install instructions
Merge branch 'master' of https://github.com/codefellows/sea-c17-ruby
adding tweak  to 7.2