Clearify readme

Author: Ruben van Vreeland

README.md

@@ -23,7 +23,7 @@ docker run -d -p 3030:3030 \
 ```
 
 _Fish_
-```fish
+```bash
 docker run -d -p 3030:3030 \
     -v (pwd)/config/elastalert.yaml:/opt/elastalert/config.yaml \
     -v (pwd)/config/config.json:/opt/elastalert-server/config/config.json \