Building my last application, everbody started to lose control over the increasing complexity of business rules, which would be added every week - most of all the app owners themselves. In the end, we had to explain the behaviour of their own app to them, because they forgot what they had defined a few weeks before.
With my current app, I see a similar situation approaching; in their daily business, the app owners face issues with singular clients which they usually convert into a business rule, like: if the current client is xy, use a different notification template.
We tried to use Lucidcharts to create some sort of diagram or wireframe to keep track of what the app is actually supposed to do. I would mark a rule in the wireframe with an ID, ie #01, and then refer that ID to the actual code. But it's hard to get everybody involved, especially non-tech people (business owners).
What would be the format to keep an organized catalog of business rules, as a reference for the coder, the project manager and the business owner?
And if someone feels like voting down this question, please explain why.