Request: Docker image with initialized environment

Hi,

thank you for providing the package!

Just a minor suggestion for the convenience of use of the Docker Image.

I pulled it as a Singularity image on our cluster. Inside the container there was no Python on the $PATH. It took me a while to look around what is where until I could run `source /usr/local/bin/_activate_current_env.sh` . It would be convenient to have the environment already initialized.

Please correct me if I missed something.
Thank you!

Petr