added back a comment that aas removed in the previous merge

Author: fabpot

web/app.php

@@ -5,7 +5,10 @@
 
 $loader = require_once __DIR__.'/../app/bootstrap.php.cache';
 
-// Use APC for autoloading to improve performance.
+// Enable APC for autoloading to improve performance.
+// You should change the ApcClassLoader first argument to a unique prefix
+// in order to prevent cache key conflicts with other applications
+// also using APC.
 /*
 $apcLoader = new ApcClassLoader(sha1(__FILE__), $loader);
 $loader->unregister();