borgbackup#2 Fix mysql backup in apps and update alerta command

tasks/apps/maven.yml

@@ -48,6 +48,7 @@
   vars:
     application: docker
     application_id: '{{ app.id }}'
+    application_db: '{{ app.id }}'
     application_remote_repo: '{{ app.borgrepo }}'
     application_root: '{{ appdir }}'
     application_backup_source: '{{ appdir }}/dbbackup'