set meta referrer tag to "always"

http://wiki.whatwg.org/wiki/Meta_referrer

lobsters isn't secret, but because it's all behind https, browsers
don't send a referrer header when visiting linked stories that
aren't behind ssl.  for site owners, it can be useful to see where a
sudden burst of traffic is coming from and view comments, so force
supporting browsers (currently only chrome) to send the lobsters
referral url.

app/views/layouts/application.html.erb

@@ -6,6 +6,7 @@
  <link rel="apple-touch-icon" href="/apple-touch-icon.png" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <meta name="robots" content="noarchive,noodp,noydir" />
  <meta name="referrer" content="always" />
  <% if @short_url %>
    <link rev="canonical" rel="self alternate shorter shorturl shortlink"
      href="<%= @short_url %>" />