Mitigate Rails vulnerability (CVE-2013-0156)

Here we apply the workaround suggested here:
  https://groups.google.com/forum/#!topic/rubyonrails-security/61bkgvnSGTQ/discussion

Change-Id: I896f163a113912bd2f302ea82fd968e9b3433f86
Reviewed-on: https://gerrit.causes.com/17269
Reviewed-by: Alex Wallace <alex.wallace@causes.com>
Tested-by: Lann Martin <lann@causes.com>