This project is just a demo show how to use container-env.
First clone, type direnv allow to make direnv trust in the file .envrc.
Second, build the container executing: build
It is done. Now your commands like irb or rubocop (and all others in CONTAINER_WRAPPERS inside .envrc) will run inside the container seamlessly.
./my_script.rb
The output should be:
I'm running inside the container
Ruby version 2.5.3 (2018-10-18) [x86_64-linux]
If you would like to use irb for example, you can use it normally, but it will run inside the container as a regular script.