chore: add backup prune, replace period flag by BACKUP_RETENTION_DAYS environment variable

docs/how-tos/backup-to-s3.md

@@ -74,6 +74,8 @@ services:
       - AWS_ACCESS_KEY=xxxx
       - AWS_SECRET_KEY=xxxxx
       # - BACKUP_CRON_EXPRESSION=0 1 * * * # Optional
+      #Delete old backup created more than specified days ago
+      #- BACKUP_RETENTION_DAYS=7
       ## In case you are using S3 alternative such as Minio and your Minio instance is not secured, you change it to true
       - AWS_DISABLE_SSL="false"
      # mysql-bkup container must be connected to the same network with your database

docs/how-tos/backup-to-ssh.md

@@ -79,6 +79,8 @@ services:
       - REMOTE_PATH=/home/jkaninda/backups
       - SSH_IDENTIFY_FILE=/tmp/id_ed25519
      # - BACKUP_CRON_EXPRESSION=0 1 * * * # Optional
+      #Delete old backup created more than specified days ago
+      #- BACKUP_RETENTION_DAYS=7
       ## We advise you to use a private jey instead of password
       #- SSH_PASSWORD=password
      # mysql-bkup container must be connected to the same network with your database

docs/how-tos/backup.md

@@ -75,6 +75,8 @@ services:
       - DB_USERNAME=username
       - DB_PASSWORD=password
       - BACKUP_CRON_EXPRESSION=0 1 * * *
+      #Delete old backup created more than specified days ago
+      #- BACKUP_RETENTION_DAYS=7
     # mysql-bkup container must be connected to the same network with your database
     networks:
       - web