For mounted volume in VM or attached volume in Docker container, you may copy your SSH public and private key to the "shared" directory, and then copy then to the virtual environment SSH folder (~/.ssh/), such as:
$ cp id_rsa ~/.ssh/id_rsa
$ cp id_rsa.pub ~/.ssh/id_rsa.pub
$ eval `ssh-agent`
$ ssh-add
Or else, generate a new SSH key pairs and add the public key to GitHub (may refer to the "Generating a new SSH Key" help documentation on GitHub)
Since rebar3 use Git to manage dependencies, this will be important step for the Erlang projects using rebar3, such as ox-http-gateway.
https://docs.docker.com/docker-cloud/cloud-swarm/ssh-key-setup/