Update Rails to 4.0.3

* Data Injection Vulnerability in Active Record
  (https://groups.google.com/forum/#!topic/rubyonrails-security/Wu96YkTUR6s)
* XSS Vulnerability in number_to_currency, number_to_percentage and
  number_to_human
  (https://groups.google.com/forum/#!topic/rubyonrails-security/tfp6gZCtzr4)