add content map entry for balanced triads

Author: mneedham

doc/docbook/content-map.xml

@@ -32,6 +32,8 @@
       </d:tocentry>
       <d:tocentry linkend="algorithms-triangle-count-clustering-coefficient"><?dbhtml filename="algorithms/triangle-counting-clustering-coefficient/index.html"?>
       </d:tocentry>
+      <d:tocentry linkend="algorithms-balanced-triads"><?dbhtml filename="algorithms/balanced-triads/index.html"?>
+      </d:tocentry>
     </d:tocentry>
 
     <d:tocentry linkend="algorithms-path-finding"><?dbhtml filename="algorithms/pathfinding/index.html"?>