deleted_by not set to null on restoring

[nstapelbroek]

Original: https://github.com/nstapelbroek/culpa/issues/12

Hi could you please add

public function restoring(Model $model) {
    $model->{$this->getColumn($model, 'deleted')} = null;
}

to the BlameableObserver, in order to also restore the deleted_by column when restoring a soft-deleted model

Thank you

[nstapelbroek]

Hi @BraunLukas ,

Thank you for your suggestion. Feel free to submit a Pull Request with the change and a small test to proof your issue is fixed.

I'm happy to assist with this. I have some time left at the end of the week if you want to.