Update Docker file/README

[bhaktasn]

Docker container doesn't allow user access to /etc/init.d/ethercat so there is no clear way to test.

Either README should include additional commands on how to test, or dockerfile/docker run command needs to be updated.

Messing with it on my own right now but would be great to hear if anyone has had any luck with this.
Cheers!

[PieterjanCottignies]

I mounted the /usr/local/etherlab dir from the host os into the container through the compose file:

volumes:
 - /usr/local/etherlab:/usr/local/etherlab
 - ... other volumes

After this I ran the linking commands from the install page:

sudo ln -s /usr/local/etherlab/bin/ethercat /usr/bin/
sudo ln -s /usr/local/etherlab/etc/init.d/ethercat /etc/init.d/ethercat
sudo mkdir -p /etc/sysconfig
sudo cp /usr/local/etherlab/etc/sysconfig/ethercat /etc/sysconfig/ethercat

Then i was able to use the ethercat commands such as ethercat slaves inside the docker container.

Hope this helps