After hours of blood sweat and tears, here is my take on a rails shopping cart application. It has features like saved carts though sessions and logins. Quantity stock with preventative measures of purchasing after item went out of stock, and more.
Public github page is here: http://drzgamer.github.io/Shopping-Cart
And Public Heroku link is here: https://afternoon-springs-95355.herokuapp.com
(Heroku server may be sleeping so give it time to wake up.)
