plugins with assets are not installed properly

Summary: When the plugins config option is used, the charm fetches the plugin onto the server(s) but if the plugin has assets, they will not become available.

What I did:

juju config discourse plugins="https://github.com/canonical-webteam/discourse-markdown-note.git"

What I expected:

The discourse-markdown-note plugin would become usable once the config action finished running.

What happened instead:

The plugin was installed on the discourse unit, but the resources (js and css) were not available to users.

Workaround:

After the config hooks finished, I ran the following commands on the discourse unit (in the /srv/discourse/current/ directory)

RAILS_ENV=production bundle install
RAILS_ENV=production bundle exec rake db:migrate
RAILS_ENV=production bundle exec rake assets:precompile

And then restarted the discourse unicorn server via systemctl.