Install cron task that rebuilds images when needed.

tools/containers_check_update_rebuild_switch__crontask_install.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+cd -P "$(dirname "$(readlink -f "$0")" )"
+
+if [[ "$PWD" != "$(printf %q "$PWD" )" ]]
+then
+    echo >&2 "WARNING: path seems unsafe: $PWD"
+fi
+
+{
+    crontab -l | grep -v containers_check_update_rebuild_switch.sh
+    echo "0 0 * * * $PWD/run_and_output_only_on_error.sh $PWD/containers_check_update_rebuild_switch.sh"
+} | crontab -