Callbacks

[levkk]

Execute arbitrary functions when any of the following events happen:

• a model is saved
• a model is created
• a model is destroyed

[siddahrta-max]

If the proposed signature callback<T: Model>(model: T) .-> T matches the intention of this issue, then I would say we can close this issue as for the enumerated Query types (insert, delete, update) a Callback exists.