Docker has not been installed on EIDF

[ramdrop]

Describe the bug In README, it says:

Build the images by running docker build . -t image-name:version from within the minimal-ml-template directory.

However, docker has not been installed on EIDF and thus running the above command would result in an error:

xxx@eidf029-host1:~$ docker build . -t image-name:version
Command 'docker' not found, but can be installed with:

snap install docker     # version 20.10.24, or
apt  install docker.io  # version 20.10.21-0ubuntu1~20.04.2

See 'snap info docker' for additional versions.

To Reproduce Steps to reproduce the behavior:

1. Log in to EIDF
2. run docker build . -t image-name:version
3. See error

Expected behavior The image is built.