必做的一個動作之一，來自官方的 repo
https://github.com/git/git
curl https://raw.github.com/git/git/master/contrib/completion/git-completion.bash -o ~/.git-completion.bash
echo "source ~/.git-completion.bash" >> ~/.bash_profile輸入
git che 再按 tab 便會自動完成還可以自動補完 branch name!!
