Registering "Task via classes" is not clear

https://github.com/rocketeers/docs/blame/master/II-Concepts/Tasks.md#L136

Which config file? config.php or hooks.php?
I think in the [hooks.php](https://github.com/rocketeers/rocketeer/blob/master/src/config/hooks.php#L32) like this: 

```
'custom' => [
    'db:migrate' => 'MyTask\Migrate'
],
```

and not the way as in the docs.
