Transitions the Docker image to use s6 and s6-overlay for process supervision instead of supervisord (#8886)

docker/management_script.sh

@@ -1,17 +1,13 @@
-#!/usr/bin/env bash
+#!/command/with-contenv /usr/bin/bash
+# shellcheck shell=bash
 
 set -e
 
-cd /usr/src/paperless/src/
-# This ensures environment is setup
-# shellcheck disable=SC1091
-source /sbin/env-from-file.sh
+cd "${PAPERLESS_SRC_DIR}"
 
-if [[ $(id -u) == 0 ]] ;
-then
-	gosu paperless python3 manage.py management_command "$@"
-elif [[ $(id -un) == "paperless" ]] ;
-then
+if [[ $(id -u) == 0 ]]; then
+	s6-setuidgid paperless python3 manage.py management_command "$@"
+elif [[ $(id -un) == "paperless" ]]; then
 	python3 manage.py management_command "$@"
 else
 	echo "Unknown user."