CORS (Cross-Origin Resource Sharing) prevented the application's
networked (multiplayer) support from working locally. The
debug_local_testing branch has changes to allow running the game
locally. The backend must be run with `cargo run --release` or `cargo
run`, and the frontend must be run with `trunk serve`, and the
browser(s) must open `http://localhost:8080/`.
The frontend "server" and backend server must be served via the same
port/address. This can be done by using nginx as the server, and using
reverse-proxies from nginx to the frontend and backend servers.
Stephen Seo