Nginx.org太壞了，竟然給的apt源是有誤。
其實應該這樣添加才行，網站給的老是報錯not found
vim /etc/apt/sources.list 添加如下
deb http://nginx.org/packages/mainline/debian/ jessie nginx
deb-src http://nginx.org/packages/mainline/debian/ jessie nginx
導入key
wget http://nginx.org/packages/keys/nginx_signing.key
apt-key add nginx_signing.key
安裝
aptitude update
aptitude install nginx