to activate the munin plugins
 - copy "osm_replication_lag" to "/opt/local/share/munin/plugins"
 - make "/opt/local/share/munin/plugins/osm_replication_lag" executable
 - symlink "/opt/local/share/munin/plugins/osm_replication_lag" to "/opt/local/etc/munin/plugins"
 - copy "osm_replication.conf" to "/opt/local/etc/munin/plugin-conf.d"
 - edit "/opt/local/etc/munin/plugin-conf.d/osm_replication.conf" and set the workingDirectory
 - restart the munin-node
