This script will read your secret file and set each line as an env variable in your container.
I' assuming that you already has a entrypoint file in your Dockerfile. So now, you need to copy and paste the contents of set_env_secrets.sh to your entrypoint(you don't need the first line).
Now, you need to create a secret, the name could be whatever you like. I'm using the name of my application as a pattern for my secrets name. For this example, my secret name will be super-project and the content will be.