Add link to the Docker NGINX unprivileged image to the NGINX docs

nginx/content.md

@@ -180,6 +180,8 @@ http {
 }
 ```
 
+Alternatively, check out the official [Docker NGINX unprivileged image](https://hub.docker.com/r/nginxinc/nginx-unprivileged).
+
 ## Monitoring nginx with Amplify
 
 [Amplify](https://amplify.nginx.com/signup/) is a free monitoring tool that can be used to monitor microservice architectures based on nginx. Amplify is developed and maintained by the company behind the nginx software.