make sure the config dir is writable for apache

Author: ylebre

Dockerfile

@@ -20,3 +20,4 @@ WORKDIR /app
 RUN php /install/composer.phar install --no-dev --prefer-dist
 COPY site.conf /etc/apache2/sites-enabled/site.conf
 EXPOSE 443
+RUN chown www-data:www-data config