How to run phpBB in Docker with NGINX, php installed on a different host than the database?

How can I run a Docker image with NGINX, phpBB (and all required stuff like php installed) with persistence (Changes on the board shouldn't be lost) and with the database on another host (which already exists). So, let's assume I have the following: MySQL on 192.168.2.233 (local address) on port 3307 running. Now I want to create a Docker image with Alpine Linux (The smallest propably), NGINX and phpBB where the board runs on the NGINX webserver and connects to the database. Changes on the board (E.g. changing the webserver settings or so) should be persisted within the container. How can I do that?

EDIT:

The database on server 192.168.2.233 is already existing! So no, I don't need two or more Docker containers. I need one Docker container with phpBB running on the NGINX webserver and connecting to the database on another host in the same network. The container should use persistence (volumes) to save the settings made in phpBB.

I tried to use the following Dockerfile and modified it: https://gitlab.com/boxedcode/alpine-nginx-php-fpm/blob/master/Dockerfile --> https://drive.google.com/open?id=1CW68OFCJE9RjIe8_RBC8q5Fa6juRtxmR

Together with the owner of another repository I've now found a solution (that uses Apache however) here: https://github.com/blueimp/phpbb/issues/1. After a few errors and problems from my side, I figured it out. The solution I'm using now is placed here: https://github.com/SeppPenner/DockerApacheSSLphpBB