[BUG] gunicorn-extra.cfg completelly overrides existing one

[b-a-t]

Tag/version of Container Images
0.5.3

The initialisation code in the docker-entrypoint.sh for mailman-core uses override shell semantics > rather than append to the end of the file >> as everywhere else in the code, where extra configs are provided.

docker-mailman/core/docker-entrypoint.sh

Line 216 in a725f3b

cat /opt/mailman/gunicorn-extra.cfg > /etc/gunicorn.cfg

if [[ -e /opt/mailman/gunicorn-extra.cfg ]]
then
       echo "Found [webserver] configuration file at /opt/mailman/gunicorn-extra.cfg"
       cat /opt/mailman/gunicorn-extra.cfg > /etc/gunicorn.cfg
fi

Not really sure if it's a bug or a feature, but at least, worth a comment in the code?