fix max servers to 5

Dockerfile

@@ -21,6 +21,8 @@ RUN chown -R www-data:www-data /app/code
 # configure apache
 RUN rm /etc/apache2/sites-enabled/*
 RUN sed -e 's,^ErrorLog.*,ErrorLog "|/bin/more",' -i /etc/apache2/apache2.conf
+RUN sed -e "s,MaxSpareServers[^:].*,MaxSpareServers 5," -i /etc/apache2/mods-available/mpm_prefork.conf
+
 RUN a2disconf other-vhosts-access-log
 ADD apache2-wordpress.conf /etc/apache2/sites-available/wordpress.conf
 RUN ln -sf /etc/apache2/sites-available/wordpress.conf /etc/apache2/sites-enabled/wordpress.conf