visionmedia/co — pull request #83 by fixe (2014-01-31 00:34:15+00:00)
Title: Add promises example

I found this useful when I tried to use mongoose save method.

```
var deferred = Q.defer();

user.save(function(error, user) {
if (error) {
deferred.reject(new Error(error));
} else {
deferred.resolve(user);
}
});

return yield deferred.promise;
```