Announce borg backup support

Related to:

- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1727
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1754
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1755
- https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/467

docs/configuring-playbook-backup-borg.md

@@ -8,6 +8,9 @@ You will need a remote server where borg will store the backups. There are hoste
 
 The backup will run based on `matrix_backup_borg_schedule` var (systemd timer calendar), default: 4am every day.
 
+By default, if you're using the integrated Postgres database server (as opposed to [an external Postgres server](configuring-playbook-external-postgres.md)), Borg backups will also include dumps of your Postgres database. An alternative solution for backing up the Postgres database is [postgres backup](configuring-playbook-postgres-backup.md). If you decide to go with another solution, you can disable Postgres-backup support for Borg using the `matrix_backup_borg_postgresql_enabled` variable.
+
+
 ## Prerequisites
 
 1. Create a new SSH key:

docs/configuring-playbook-postgres-backup.md

@@ -2,6 +2,9 @@
 
 The playbook can install and configure [docker-postgres-backup-local](https://github.com/prodrigestivill/docker-postgres-backup-local) for you.
 
+For a more complete backup solution (one that includes not only Postgres, but also other configuration/data files), you may wish to look into [borg backup](configuring-playbook-backup-borg.md) instead.
+
+
 ## Adjusting the playbook configuration
 
 Minimal working configuration (`inventory/host_vars/matrix.DOMAIN/vars.yml`) to enable Postgres backup:

docs/configuring-playbook.md

@@ -152,6 +152,13 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 - [Setting up Mjolnir](configuring-playbook-bot-mjolnir.md) - a moderation tool/bot (optional)
 
 
+### Backups
+
+- [Setting up borg backup](configuring-playbook-backup-borg.md) - a full Matrix server backup solution, including the Postgres database (optional)
+
+- [Setting up postgres backup](configuring-playbook-postgres-backup.md) - a Postgres-database backup solution (note: does not include other files) (optional)
+
+
 ### Other specialized services
 
 - [Setting up the Sygnal push gateway](configuring-playbook-sygnal.md) (optional)