Pack install from private repository with ssh using docker image (how to)

[wajih-ats]

Is your feature request related to a problem? Please describe.
The documentation does not mention how to use ssh to install pack from private repository when using docker.

Describe the solution you'd like
Clear documentation on how to use my ssh key in the docker-compose file (maybe an env var)

Describe alternatives you've considered
None

[arms11]

I wonder if this is more suitable for stackstorm forum.

[arm4b]

Replied in https://forum.stackstorm.com/t/how-to-install-pack-from-private-git-repository-using-ssh-when-deployed-on-docker/1500/2

There is some info in https://docs.stackstorm.com/packs.html#installing-packs-from-private-repositories, but I guess there is a room for improvement.

@wajih-ats The Docker and Documentation repositories are opensource, we'd welcome PRs to improve the documentation around this.