install redis and hiredis gems
create redis.rb and set up redis connection
generate carts controller with show action
update routes with cart resources
update carts controller with redis actions
add cart to top menu bar
add cart_count method to user model
add cart button to movies/show
update movies:show action
add cart_action method to movie model
remove turbolinks.js; add jquery and ajax calls to carts.js
update cart/show page with current selections
add styles to carts.css.scss
add remove from cart script to carts.js.coffee