Laravel 5 - Handling empty select input on edit page

in my create function, I pass my view a list of users which I then display. However, I have changed it to the following

<select class="internalWork" name="internalWork">
    <option value=""></option>
    @foreach($users as $user)
        <option value="{{ $user->userName }}">{{ $user->userName }}</option>
    @endforeach
</select>

So I have added an empty option before the list is displayed. This is fine because this tables column allows null input.

In my edit function, I get the list

$users = User::lists('userName', 'userName');

I then pass this to my edit view. In my edit view, I have the following

<div class="form-group">
    {!! Form::label('internalWork', 'Internal work for:', array('class' => 'col-sm-5 control-label red')) !!}
    <div class="col-sm-7">
        {!! Form::select('internalWork', $users, null, ['class' => 'internalWork']) !!}
    </div>
</div>

If I selected a user in the create, then when I go to the edit page, that user is selected by default. However, if I do not select a user in the create, on the edit page, the first user in the list is displayed by default.

How can I get it to display an empty input if the database value is null?

Thanks

via Chebli Mohamed