Purge the [Nginx](http://nginx.org) cache (FastCGI, Proxy, uWSGI) automatically when content changes or manually within WordPress.
Requirements:
* The [Filesystem API](http://codex.wordpress.org/Filesystem_API) needs to function without asking for credentials.
* Nginx and PHP need to run under the same user, or PHP’s user needs write access to Nginx’s cache path.
