Use global memcache for usermeta object cache

Attempts to fix issue #114.

docker/wp-config.php

@@ -168,9 +168,16 @@ define('NOSPAM_API_URL', 'http://nospam.investici.org:9001');
  * Memcache servers for Wordpress object caching.
  */
 $memcached_servers = array(
+  // Cache most things locally.
   'default' => array(
     '127.0.0.1:7108'
-  )
+  ),
+
+  // User metadata (including session ticket info) needs to be global.
+  // See issue #114.
+  'userlogins' => $noblogs_config['memcached'],
+  'usermeta' => $noblogs_config['memcached'],
+  'user_meta' => $noblogs_config['memcached'],
 );
 
 /*