Fix tests of 01-Ruby / 04-Hash-Symbols / Optional-03-Shopping-Cart
Update exercise README
Merge pull request #24 from lewagon/01-Ruby/04-Hash-Symbols/Optional-03-Shopping-Cart

Fix tests of 01-Ruby / 04-Hash-Symbols / Optional-03-Shopping-Cart
Merge branch 'master' of github.com:lewagon/promo-3-challenges
read & write sur le csv