If you did not need any credentials to get to this page

gem sources -a <%= url "/" %>
If you needed some credentials to get to this page
gem sources -a <%= url.to_s.gsub('://','://username:password@') %>
and then ...
gem install geminabox
gem inabox [gemfile]

<% if @gems.any? %> ">Upload Another Gem
<%= ("a".."z").map{|i| @index_gems.include?(i) ? "#{i}" : i }.join(" - ") %>
<% end %> ">Upload Another Gem