integrates serviceworker-rails with webpacker

[ncs1]

Hi,
I'm trying to integrate this gem on a Rails 6.0.3.1 with webpacker project.
The installer generator provided, crash due to:
app/assets/javascripts/application.js does not appear to exist
+The instructions in the gem are specifically tailored for sprockets and not webpacker, although it's stated to support webpacker also in the beginning.
Can you please clarify how it can be integrated with webpacker ?
Thanks.