Update backup.rst

Fix relative path

docs/databases/backup.rst

@@ -1,7 +1,7 @@
 Docker database backup
 ======================
 
-This page explains how to automate the backup process of a Docker database on a daily basis and restore the backup snapshot created by the `backup script <../scripts/backup.sh>`_.
+This page explains how to automate the backup process of a Docker database on a daily basis and restore the backup snapshot created by the `backup script <../../scripts/backup.sh>`_.
 
  Note: This documentation assumes that you are using a Linux-based system.
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