How to add ash script in LuCI menu?

I have a little ash script that helps me to get some information of my OpenWRT router directly via LuCI intercace. For exemple I can see the openvpn.log on the browser.
The script /www/cgi-bin/vpn-log looks like:
echo "Content-type: text/html"
echo ""
echo "<html><head><title>See openvpn.log"
echo "</title></head><body>"
echo "<h1>See openvpn.log</h1>"
echo "<pre> $(cat /var/log/openvpn.log) </pre>"
echo "<center>Info from $(date)</center>"
echo "</body></html>"

I can see the result calling http:/

My question is, how to create an LuCI topic in the Menu to call this script?

I hav tried with the instructions given in without success.