http://www.liaoxuefeng.com/wiki/0013739516305929606dd18361248578c67b8067c8c017b000
https://github.com/geeeeeeeeek/git-recipes/wiki
http://www.ruanyifeng.com/blog/2014/06/git_remote.html
http://rogerdudler.github.io/git-guide/index.zh.html
https://marklodato.github.io/visual-git-guide/index-zh-cn.html#checkout