WEB_DOCUMENT_ROOT accept argument DOCUMENT_ROOT with original default value /var/www/

apache2/Dockerfile

@@ -5,10 +5,11 @@ LABEL maintainer="Eric Pfeiffer <computerfr33k@users.noreply.github.com>"
 ARG PHP_UPSTREAM_CONTAINER=php-fpm
 ARG PHP_UPSTREAM_PORT=9000
 ARG PHP_UPSTREAM_TIMEOUT=60
+ARG DOCUMENT_ROOT=/var/www/
 
 ENV WEB_PHP_SOCKET=${PHP_UPSTREAM_CONTAINER}:${PHP_UPSTREAM_PORT}
 
-ENV WEB_DOCUMENT_ROOT=/var/www/
+ENV WEB_DOCUMENT_ROOT=${DOCUMENT_ROOT}
 
 ENV WEB_PHP_TIMEOUT=${PHP_UPSTREAM_TIMEOUT}