sitename.erb

server {
        listen   80;
        server_name sitename.com;
        access_log  /var/log/nginx/sitename.access.log;
        root   /opt/sites/sitename.com;
        index  index.html index.htm;

	location ~* ^.+\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf)$ {
	    expires max;
	    access_log off;
  	}
}