Laravel: is it possible to do orWhere(Model::find())?

I am using Lumen Laravel 5.1. I have a many to many relation between task and user, and pivot table called task_user, I recently asked this question, inspired by the answer and by reading the documentation, I think I can do this

$users = User::tasks()
        ->where('domain_id', $domainId)
        ->where('created_by', $userId)
        ->orWhere(User::tasks()->find($userId))
        ->Where(function ($query) {
            $query->where("is_done", 0)
                ->orderBy('due_date', 'DESC');
        })
        ->Where(function ($query) {
            $query->Where("is_done", 1)
                ->Where("closed_dated", Carbon::today())
                ->orderBy('closed_date', 'ASC');
        })
        ->get();

Before I accept his answer I have two questions:

1- A user can have his id related to a task, in 2 places

• task_user table if is an assignee
• created_by in tasks table, if he created it

So I want to know if he's an assignee or if he created it, both cases I want to display his tasks. Found nothing on google, so can I do this?

where(....) -> orwhere(model::find())

2. My second question is: Should I use ->pivot->id to get to task, instead of find()? The docs about ->pivot are confusing and the tutorials I read don't use it. I don't know if it helps me.

via Chebli Mohamed