relocate twitter feed to top

part of delivering on gitlab-com/infrastructure#471

/cc @jnijhof

See merge request !3

Favicon, README fix, LICENSE

- Adds a Favicon
- Fixes the README rendering incorrectly
- Adds a license (Same as is used in GitLab CE, but with 2015-2016 for copyright date)

/cc @jnijhof 

See merge request !2

Same as the main GitLab.com site

Update Status page Rails app

This updates the Gemfile dependencies and reduces the file load by 400KB, from 1.2MB to just under 800KB.

Changes:
- Update to Rails 4.2.5.1
- Update gems, Unicorn is now using the same version as GitLab CE
- Remove jQuery since we aren’t using it anywhere
- Remove Bootstrap.js since we aren’t using it anywhere
- Made copyright year dynamic so it will auto-update

See merge request !1

- Update to Rails 4.2.5.1
- Update gems, Unicorn is now using the same version as GitLab CE
- Remove jQuery since we aren’t using it anywhere
- Remove Bootstrap.js since we aren’t using it anywhere
- Made copyright year dynamic