Related objects should not be set directly on the Model

[snurra]

Doing it that way is just asking for trouble. Sooner or later someone will set up a relation with a name that clashes with an already existing Backbone.Model property or method. Plus it's ugly.

I suggest storing them in Backbone.RelationalModel._relations.

A consequence is that Backbone.RelationalModel.someRelation will stop working. However, there is already the alternative (or even preferable) way of Backbone.Model.get("someRelation").

[snurra]

Let's save this until 1.0 since it will be a breaking change.