Author/speakers can link to member page

If author/speaker is a member's name (or short name, or alias),
a link to the members' page will be set.

content/members/index.erb

@@ -5,7 +5,7 @@ kind: page
 <p>Hier finden sich ein paar Infos zu einigen unserer Mitglieder.</p>
 
 <% @items.select { |i| i[:kind] == 'member' }.each do |member| %>
-<h2><a id="<%= member[:title] %>"><%= member[:title] %></a></h2>
+<h2 id="<%= html_escape(member_short_name(member)) %>"><%= member[:title] %></h2>
 <ul>
   <% if member[:pgp] %>
   <li>PGP-Key: <a href="https://sks-keyservers.net/pks/lookup?op=get&search=<%= member[:pgp] %>"><%= member[:pgp] %></a></li>