http://nginx.org/en/linux_packages.html#stable
sudo apt-key add nginx_signing.key
deb http://nginx.org/packages/debian/ codename nginx deb-src http://nginx.org/packages/debian/ codename nginx
deb http://nginx.org/packages/ubuntu/ utopic nginx deb-src http://nginx.org/packages/ubuntu/ utopic nginx
apt-get update apt-get install nginx