Update handlers documentation

**Feature request**
It would be great to have backup for models.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_backup` with default `false`.

Start by locating the handlers documentation and the existing model configuration entry points. Determine where the proposed enable_backup option belongs and how its false default should be documented. Done means the backup behavior and configuration are clearly specified for production deployments, with the relevant documentation updated.

Written by the indexing model from the issue text.