Hardcoded API server address breaks deployment across multiple servers.

[larsgeb]

Realtime-Pub-Quiz/quizzer/src/websocket.js

Line 15 in a0a0a89

const serverHostname = `localhost:${PORT}`;

One line in the websocket.js file still uses a hardcoded server location; localhost. This gave some problems when running the servers on separate machines. I think it is nice to allow one to set this URL from an environment variable. Now, when reading a url from the environment variable, typically it is lead by http://. This needs to be replaced by ws://.

I'll update this in a PR. 😉

[aaron5670]

I look forward on your PR. 😃