add ``` bash

docker/README.md

@@ -2,18 +2,18 @@
 
 ## build image from Docker file
 
-''''
+``` bash
 docker build -t jgrelet/oceano2python:3.6 -f Dockerfile .
-''''
+```
 
 ## pull pull the existing images from Docker hub
 
-''''
+``` bash
 docker pull jgrelet/oceano2python:3.6
-''''
+```
 
 ## run the container
 
-''''
+``` bash
 docker run -it --rm -v /D_DRIVE:/data -e CRUISE="$CRUISE" -e DRIVE=/data python jgrelet/oceano2python:3.6 /bin/bash
-''''
+```