feat(backup): Added backup cron and helper script.

Backs up all of the data to the /backup dir.

MR !1

include/bin/backup.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+
+set -e
+
+backup_version=1.0
+back_file_name="mail_server-$backup_version-$(date +%Y-%m-%d-%H%M-%Z).tar.gz"
+
+start=$(date '+%s')
+
+includes=(/srv/mail)
+includes+=(/ssl)
+includes+=(/var/spool/spamassassin)
+includes+=(/var/log)
+includes+=(/var/lib/amavis)
+
+
+backup_command="tar -czpvf $back_file_name ${includes[@]}"
+
+cd /tmp
+
+echo "$backup_command"
+
+if ! $backup_command; then
+  status="tar failed"
+elif ! mv "/tmp/$back_file_name" /backup/ ; then
+  status="mv failed"
+else
+  status="success: version=$backup_version size=$(stat -c%s /backup/$back_file_name) duration=$((`date '+%s'` - $start)) command='$backup_command'"
+fi
+
+
+logger -t backup "$status"
+
+
+if [ "0$POST_MASTER_EMAIL" != "0" ]; then
+
+cat << EOF | /usr/lib/dovecot/dovecot-lda -d "${POST_MASTER_EMAIL}" -o "plugin/quota=maildir:User quota:noenforcing"
+Auto-Submitted: auto-generated
+Date: $(date +'%a, %-d %b %Y %H:%M:%S %z')
+To: ${POST_MASTER_EMAIL}
+From: Mail Server <NO-REPLY@$(hostname -f)>
+Subject: Backup $(date +%Y-%m-%d-%H:%M-%Z)
+
+Server backups have occured on $(hostname -f)
+
+Summary:
+
+    $status
+
+EOF
+
+fi
+

include/etc/cron.d/container_backup

@@ -0,0 +1,6 @@
+#
+#  Backup the docker container 
+#
+# m h dom mon dow user  command
+01 0,3,6,9,12,15,18,21	* * *	root	/bin/backup.sh 2>&1
+