Rebase to 3.17, use build-base for unrar build.

root/etc/s6-overlay/s6-rc.d/init-qbittorrent-config/run

@@ -1,4 +1,5 @@
 #!/usr/bin/with-contenv bash
+# shellcheck shell=bash
 
 # make our folder
 mkdir -p /config/qBittorrent

root/etc/s6-overlay/s6-rc.d/svc-qbittorrent/run

@@ -1,4 +1,5 @@
 #!/usr/bin/with-contenv bash
+# shellcheck shell=bash
 
 WEBUI_PORT=${WEBUI_PORT:-8080}