[git] git server & git command

http://toyroom.bruceli.net/tw/2011/02/04/install-git-server-on-ubuntu-linux.html
https://git-scm.com/book/zh-tw/v1/%E4%BC%BA%E6%9C%8D%E5%99%A8%E4%B8%8A%E7%9A%84-Git-%E6%9E%B6%E8%A8%AD%E4%BC%BA%E6%9C%8D%E5%99%A8