Update docs/configuring-playbook-backup-borg.md

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-backup-borg.md

@@ -10,10 +10,13 @@ The backup will run based on `backup_borg_schedule` var (systemd timer calendar)
 
 By default, if you're using the integrated Postgres database server (as opposed to [an external Postgres server](configuring-playbook-external-postgres.md)), backups with BorgBackup 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 BorgBackup using the `backup_borg_postgresql_enabled` variable.
 
+**Note**: the `matrix-backup-borg` role is not managed by this repository but its [own repository](https://github.com/mother-of-all-self-hosting/ansible-role-backup_borg).
 
 ## Prerequisites
 
-1. Create a new SSH key:
+1. Make sure that the Postgres version of your homeserver's database is compatible with borgmatic.
+
+2. Create a new SSH key:
 
     ```bash
     ssh-keygen -t ed25519 -N '' -f matrix-borg-backup -C matrix
@@ -21,7 +24,7 @@ By default, if you're using the integrated Postgres database server (as opposed
 
     This can be done on any machine and you don't need to place the key in the `.ssh` folder. It will be added to the Ansible config later.
 
-2. Add the **public** part of this SSH key (the `matrix-borg-backup.pub` file) to your BorgBackup provider/server:
+3. Add the **public** part of this SSH key (the `matrix-borg-backup.pub` file) to your BorgBackup provider/server:
 
     If you plan to use a hosted solution, follow their instructions. If you have your own server, copy the key over: