$ make build docker_tag="tkuchiki/embulk"
$ make build docker_tag="tkuchiki/embulk" jdk_version="8" embulk_version="0.9.7"
# show help
$ docker run tkuchiki/embulk
# show version
$ docker run tkuchiki/embulk --version
# embulk gem install & embulk preview
$ docker run -v $(pwd)/config.yml:/tmp/config.yml -v $(pwd)/plugins.txt:/opt/embulk/plugins.txt --rm -it tkuchiki/embulk preview /tmp/config.yml