remove unnecessary files. [ci skip]
add build to default target. [ci skip]
add usage section. [ci skip]
Merge pull request #103 from wakameci/docs

Docs
update buildbook.
Merge pull request #104 from wakameci/update-buildbook

update buildbook.
add setup to default task.
update usage section.
Merge pull request #105 from wakameci/makefile

Makefile
replace fstab-cgroup with buildbook.