add command to dump test database

README.md

@@ -15,3 +15,6 @@ The test database is a small collection of wiki pages, boards, and posts. There
 
 ### Follow PHP logs
 `docker exec glitchcityinfo_web_1 tail -f /var/log/php5-fpm.log`
+
+### Dump test database
+`docker-compose exec db mysqldump glitchcity -ptoor`