Indicate on the site dashboard whether hosts are redirected by GDS

I did a prototype-ish of this yesterday—any thoughts on this?

![screen shot 2014-09-03 at 12 41 12](https://cloud.githubusercontent.com/assets/355033/4133521/a1a46478-335f-11e4-9a1a-cd13ffc32ac3.png)

`host.ip_address == '46.137.92.159'` belongs in the `redirected_by_gds?` method. It also needs at least one spec.