Laravel - How to get the id of custom pivot table

Let's say you have a custom pivot table that is defined this way

lass UserReward extends Pivot
{
    ...
    ...
    ...
}

If you simply work with this table you as a model you will realise that the ID of the table was omitted.
To get the ID add the you need to override the $incrementing property of the parent Pivot table.

lass UserReward extends Pivot
{
    public $incrementing = true;
    ...
    ...
    ...
}