Run a monthly restic check

Every month, a restic check is run, to see if there are any problems
with the repositories snapshot, index, or pack structures.  This does
not actually read any of the packs, though, since that can involve a lot
of data-download charges.

root/etc/periodic/monthly/check.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+# vim: ts=4 sw=4 noet
+
+# This script runs our backups!
+
+set -eu
+set -o pipefail
+
+# PART 0: Check environment
+# No environment needed!
+
+# PART 1: Run check
+restic check