dhruvaray/backbone-associations — pull request #111 by mrAdm (2014-02-24 18:37:26+00:00)
Title: Removing references from parents

```javascript
var Foo = Backbone.AssociatedModel.extend({});

var Bar = Backbone.AssociatedModel.extend({
relations: [{
type: Backbone.One,
key: 'rel',
relatedModel: Foo
}]
});
```
Create some instances:
```javascript
var foo1 = new Foo;
var foo2 = new Foo;

var bar = new Bar({rel: foo1});
```
Now foo1.parents contains one element (bar).
Next, change rel attribute:
```javascript
bar.set({rel: foo2})
```
Conceptually, bar must retire from foo1.parents, but it is'nt.
```
foo1.parents.length => 1
foo2.parents.length => 1
```