Use HTTP source instead of HTTPS for rubygems.org

Fixes this error:

Gem::RemoteFetcher::FetchError: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://s3.amazonaws.com/production.s3.rubygems.org/gems/rack-1.5.2.gem)
The start of a dashboard UI, hard-coded and very hacky