The custom method for conditional audits cannot be a private method

[mstroming]

The documentation here gives an example of a custom method being a private method. That doesn't work in version 4.7.x. The method does not get called if it's private.

https://github.com/collectiveidea/audited/tree/v4.7.1#conditional-auditing

There are many outstanding pull requests so I decided to open an issue instead of correcting the documentation.