Touch the parent model when assigning tags?

[bjhijmans]

Hi,

When I call $model->syncTags($tags) (or one of the other methods) I want to touch $model if any tags have changed.

However, looking at the code, the only way to do that is to override all those methods and do it manually. I currently only use syncTags, and I added the following to it:

       $result = $this->tags()->sync($tags->pluck('id')->toArray());

        if (array_filter($result)) {
            $this->touch();
        }

Is there a better way to do this? Or any interest to make this part of the package (as a config option)? I'd consider making a PR for it.