Use secrets for env variables?

[muety]

I'm still quite new to Kubernetes, but I've read that Kubernetes secrets provide a way to securely pass credentials etc. to containers.
In kubernetes/api-deployment.yaml, CLIENT_ID etc. are hard-coded, which is probably not a good practice, since those files are mentioned to be committed to VCS. I'd like to have the workshop being extended in a way that it should how to properly handle such confidential variables 🙂.