thanks mics8128 and sammy007
docker run --restart unless-stopped -p 8546:8546 -p 8080:8080 -v /proxyconfig/config.json:/config.json -e CONFIG=/config.json babim/ether-proxy
-e CONFIG=/config.json to config file. Default: /opt/ether-proxy/ether-proxy/config.json
example file: https://raw.githubusercontent.com/babim/ether-proxy/master/config.json