add assets for ratings

http://paweljaniak.co.za/2013/07/25/5-star-ratings-with-rails/

git add app/assets/javascripts/jquery.raty.min.js
git add app/assets/images/star-on.png
git add app/assets/images/star-off.png
start to add ratings back

http://paweljaniak.co.za/2013/07/25/5-star-ratings-with-rails/

for i in overall_averages average_caches rates rating_caches; do rails g migration drop-$i; done
reverse up and down from old tables
rake db:migrate

rails g model Rating book:references user:references stars:integer
migration: s/:stars/:stars default: 0/

book and user:
has_many :ratings

routes:
  resources :ratings, only: :update

add stars to view
get or define @rating in bookscontroller show
put some crazy js in application.html.haml
define update in RatingsController
put almost identical js in app/views/ratings/update.js.erb