You will need a dedicated server or VDS.
npm i express
npm i discord-webhook-node
For demonize nodejs process you can use PM2
npm i pm2 -g
pm2 start index.js --name luaerrors
IN config.json
webhook - Your discord webhook
img - Webhook avatar
port - your webserver port
route - random it's need for http://localhost:1488/itsroute
Put lua_error_url "http://localhost:1488/itsroute"
in the garrysmod/cfg/server.cfg and restart server.
Send lua errors to Discord using webhooks.