changed docker file nest to avoid rebuild everything each time, and small changes in chat gateway

tests_hugo/with_express/server.js

@@ -0,0 +1,10 @@
+const express = require('express')
+const server = express()
+
+server.get('/', (req, res) => {
+	res.sendFile(__dirname + "/" + "index.html")
+})
+
+const port = 3000
+server.listen(port, console.log(`listening on port ${port} with express`));
+