briankircho/mongoose-schema-extend — pull request #24 by voz (2014-03-06 12:03:18+00:00)
Title: Fixes a bug when fn is not defined

In some cases I was getting the following error:

```console
node_modules/mongoose-schema-extend/index.js:67
fn.apply(this, arguments);
^
TypeError: Cannot call method 'apply' of undefined
```

This request fixes the problem.