Added the possibility to run a custom startup script in addition to the existing ones

[MephistoJB]

No description provided.

[Mincka]

Why?

[MephistoJB]

Because I need a few lines of code executed before the start of firefox. I do not see another way to achieve that without building my own image (which I would like to avoid)

[MephistoJB]

Another idea: Maybe it would be more elegant, if the path to the script would be an env var.

[Mincka]

Because I need a few lines of code executed before the start of firefox. I do not see another way to achieve that without building my own image (which I would like to avoid)

Can you give more details about what you'd like to run?
I don't like the idea to be able execute anything on the container.

If you need to install something, you could execute something directly on the container with SSH and create commands for that:
https://community.home-assistant.io/t/run-docker-exec-from-shell-command-integration-or-other-tricks/400810/7?u=mincka

You could even trigger it on add-on (re)start with one of the method explained here:
https://community.home-assistant.io/t/trigger-automation-when-hassio-addon-starts-stops/47616?u=mincka