How to add http_proxy to docker version of StackStorm?

Hello all,
I need to go through proxy to get to the internet. I managed to install and run the whole StackStorm set in docker using the provided docker-compose.

However I can’t figure out where to setup the http_proxy so I can install/download packages from internet. Documentation is saying:

On Ubuntu systems, edit /etc/default/st2actionrunner and /etc/default/st2api to set the proxy configuration environment variables. For RHEL/CentOS systems, edit /etc/sysconfig/st2actionrunner and /etc/sysconfig/st2api .

But this files are not present in the docker images…

Any ideas ? Thanks.