I am working on an existing project that was built by Droopler distribution and docker4drupal. As per Droopler distribution documentation, it requires npm and gulp to compiled sass easily and docker4drupal don't have it by default.
I tried to install in the container by sudo apt-get install npm
and it says:
sudo: apt-get: command not found
Is there any way to install npm and gulp in docker4drupal for my existing project?