Fixing error before/let in cart_spec
Merge pull request #19 from lewagon/01-04-opt03-spec-error

Fixing error before/let in cart_spec
re-ordering OO challenges
Merge branch 'master' of github.com:lewagon/promo-3-challenges
Merge branch 'master' of github.com:lewagon/promo-3-challenges
finalised array to hash