Class 'AbstractMigration' not found

when calling 

```php
php cake.php bake migration Initial -c default
````
the migration file is created with the correct table datas. but, when calling

```php
php cake.php migrations migrate
```

i'm receiving an error. 

```
Class 'AbstractMigration' not found in /vagrant/APP_NAME/config/Migrations/20141204113546_initial.php on line 2
```

it looks like "use"-statement wasn't correctly placed inside the generated <?php tag.