add read.js and write.js to be precompiled so it's /assets/read.js not /javascripts/read.js

@veganstraightedge I figured out why it was using the odd url for the javascripts. It's because the layout includes read.js and write.js and those weren't being precompiled by heroku, and so it was using a fallback route.

I also upgraded the app's gems and removed the redundancy of having the ruby version specified both in .rvmrc and Gemfile.