fix for #1808

[georglauterbach]

Description

Bugfix and small improvement for setup.sh

Fixes #1808

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (non-breaking change that does improve existing functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• [] I have made corresponding changes to the documentation (README.md or ENVIRONMENT.md or the Wiki)
• If necessary I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[georglauterbach]

Please note that the deletion of mail users now strictly follows the setup.sh help text, deleting only one user at a time. This is intended and does not actually introduce changes technically, since the documentation always stated that it was exactly this way.

[casperklein]

Instead of array elements, why not using normal vars that are more readable/intuitive to understand? 😎

Something like this:

USER="${*}"               -->  EMAIL="${*}"

MAILARR[0]="${USER%@*}"   -->  USER="${USER%@*}"
MAILARR[1]="${USER#*@}"   -->  DOMAIN=${USER#*@}"

[wernerfred]

But then using EMAIL and not USER ;)