This is the coach with Chrome and Firefox installed.
Read the docs at Github.
docker run --rm sitespeedio/coach https://www.sitespeed.io
docker run --privileged --rm sitespeedio/coach https://www.sitespeed.io -b chrome
docker run --rm -v "$(pwd)":/coach sitespeedio/coach https://www.sitespeed.io -o advice.json -f json