Update RUNBOOK.md (#59)

fix name of mediawiki-volume

RUNBOOK.md

@@ -16,7 +16,7 @@ Please follow below instructions in order to upgrade the mediawiki version. Refe
 1. Take a backup! Run `docker-compose -f docker-compose.yml -f docker-compose.override.yml -f docker-compose.prod.yml exec backup ./run_backup.sh` and make sure it succeeded. Also run `git log` and note down the current deployed sha, in case you need to roll back.
 1. `git pull` and `docker-compose build`. This builds and caches the new images locally without interrupting the old server, which reduces downtime.
 1. `docker-compose -f docker-compose.yml -f docker-compose.override.yml -f docker-compose.prod.yml down` shuts down the server and removes containers. Now downtime has started ticking.
-1. `docker volume rm <mediawiki-volume>`, so that the mediawiki container can create a new volume with updates in the next step.
+1. `docker volume rm metakgp-wiki_mediawiki-volume`, so that the mediawiki container can create a new volume with updates in the next step.
 1. `docker-compose up --build -d` starts all the services using the newly built images. Server is back online, verify by going to the wiki in a browser. If there are database problems, it's often fixed by running `docker-compose -f docker-compose.yml -f docker-compose.override.yml -f docker-compose.prod.yml exec php /srv/mediawiki/maintenance/update.php`.
 
 ## Docker