Improve documentation

[eXeC64]

Documentation for the DynamicDocument and DocumentId is weak to non-existent. Please provide more detailed examples for these and information on when each should be used.

[entone]

Yeah, should be able to get to it this week.

DynamicDocument is useful for creating a reference to another model that you don't know the type at compile-time. It can take any type of model and create a reference to it.

DocumentId is for when you need to enforce the model type of the relationship.

Thanks for your interest.

I'll update the docs soon.