demo project for django channels tutorial
https://channels.readthedocs.io/en/stable/tutorial/index.html
npm run build
pip3 install -U channels_redis
docker run -p 6379:6379 -d redis:5
pip3 install -U channels
cd backend
python3 manage.py runserver
go to chrome, access the following URL: http://127.0.0.1:8000/chat/
enter lobby, then click Enter to go to room page