The "addons" directory contains game server addons (plugins, extensions, etc) 
that enhance your server installation. Addons are optional but certain 
PsychoStats features require the use of one or more of these addons and it is 
up to you if you want to install them on your game server.

See the online documentation for help installing these addons here: 
http://www.psychostats.com/doc/Addons