81 Upgrade for security and performance

- Upgrading Rails version for security matters. Source: Heroku blog post "Rails Security Vulnerability" ( https://blog.heroku.com/archives/2013/1/11/rails_security_vulnerability/ )

- Upgrading Ruby version to 1.9.3 and beautifying of gemfile for performance matters according to the article "Speeding Up Heroku Boot Time for Rails app" ( http://webcache.googleusercontent.com/search?q=cache:5XICWnTYQiMJ:devign.me/speeding-up-heroku-boot-time-for-rails-app-beating-the-error-r10-boot-timeout/+&cd=7&hl=en&ct=clnk )