Upgrade to Rails 4.1.1.

- Remove zeus in favour of spring
- Update config files to match a new Rails 4.1.1 project
- Move secret_token to secrets.yml
- Group gems into environments properly.
Merge pull request #6 from Soliah/master

Upgrade to Rails 4.1.1.
Merge branch 'master' of github.com:CodeforAustralia/public-site into develop