[Radiant] setting Cache-Control for static assets

[craayzie]

I've got Radiant deployed on Heroku and wanted to have it serve a
static site in addition to my Radiant site. I used rack-rewrite to map
requests for the static site to the right location but I'm not sure
how to add the proper Cache-Control response header. Could you please
point me in the right direction? Frankly, I'm not sure if rack-rewrite
is the best solution here - it was just the first one I tried which
appears to be working (aside from not sending any down-stream caching
headers).

config/environment.rb:
Radiant::Initializer.run do |config|
...
config.middleware.insert_before(Rack::Lock, Rack::Rewrite) do
  send_file %r{.*}, 'public/static_site$&', :if => Proc.new { |
rack_env|
          rack_env['HTTP_HOST'] =~ /www.static-site.com($|:3000)/
    }
end
...

Thanks!