Host github pages under github.io domain

GitHub已将个人及项目主页地址中".com"转换成".io".

REF: https://help.github.com/articles/should-i-rename-username-github-com-repositories-to-username-github-io

Signed-off-by: Yang Hu <gumuyueying@gmail.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>