#5 Improve validation logic

1- Triggering validation automatically previous to CRUD operations makes this operations difficult to extend, since validation would be triggered after the custom behavior if you call parent::operation() on the last line of the method.

2- Rules use to be different previous to insertion than after insertion.

3- As rules are static it's impossible to validate based on dynamic data.

Still I think validation rules belong to models. One approach could be to craft a pre-insertion and a post-insertion validation method. An approach could be to

Wow! That approach seems very convincing to me, but I think it would be better to