Update docker instructions in README...

...  to match latest Dockerfile changes

README.md

 You can run it with the following bash command :
 
 ```
-docker run -it --publish 5001:80 --volume "$(pwd)/wbo-boards:/opt/app/server-data" lovasoa/wbo:latest
+docker run -it --publish 5001:8080 --volume "$(pwd)/wbo-boards:/opt/app/server-data" lovasoa/wbo:latest
 ```
 
 This will run WBO :