I have a dockerized React.js application that connects to a (also dockerized) backend written with actix-web in Rust. I have a development docker-compose file as well as a production one and am looking for a way to dynamically change the backend URL depending on the configuration in the frontend. What would be the most elegant way to achieve this? Note that environment variables are difficult in this situation, as they cannot be dynamically changed after the production frontend is built.