PHP/HHVM

First, install HHVM:

https://www.digitalocean.com/community/tutorials/how-to-install-hhvm-with-nginx-on-ubuntu-14-04

For better performance, set up HHVM as a UNIX socket to reduce additional load from TCP layers.

https://docs.hhvm.com/hhvm/advanced-usage/fastCGI#using-fastcgi

Add