hasMany relationship issue in Laravel 5.3 + MongoDB library 'jenssegers/laravel-mongodb'

I am using MongoDB library http://ift.tt/1qxFWF0 in Laravel 5.3. I have two collections in MongoDB and I want to make a hasMany relation b/w them.

MongoDB:

1st Collection: Employee

{
    "_id" : ObjectId("586ca8c71a72cb07a681566d"),
    "employee_name" : "John",
    "employee_description" : "test description",
    "employee_email" : "john@email.com",
    "updated_at" : "2017-01-04 11:45:20",
    "created_at" : "2017-01-04 11:45:20"
},
{
    "_id" : ObjectId("586ca8d31a72cb07a6815671"),
    "employee_name" : "Carlos",
    "employee_description" : "test description",
    "employee_email" : "carlos@email.com",
    "updated_at" : "2017-01-04 11:45:20",
    "created_at" : "2017-01-04 11:45:20"
}

2nd Collection: Task

{
    "_id" : ObjectId("586ccbcf1a72cb07a6815b04"),
    "task_name" : "New Task",
    "task_description" : "test description",
    "task_status" : 1,
    "task_created_at" : "2017-04-01 02:17:00",
    "task_updated_at" : "2017-04-01 02:17:00"
},
{
    "_id" : ObjectId("586cd3261a72cb07a6815c69"),
    "task_name" : "2nd Task",
    "task_description" : "test description",
    "task_status" : 1,
    "task_created_at" : "2017-04-01 02:17:00",
    "task_updated_at" : "2017-04-01 02:17:00"
}

I have created pivot table between them

Employee_Task

{
    "_id" : ObjectId("586cd0cb1a72cb07a6815bf3"),
    "employee_task_employee_id" : "586ca8c71a72cb07a681566d",
    "employee_task_task_id" : "586ccbcf1a72cb07a6815b04",
    "status" : 1
},
{
    "_id" : ObjectId("586cd7851a72cb07a6815d7d"),
    "employee_task_employee_id" : "586ca8c71a72cb07a681566d",
    "employee_task_task_id" : "586cd3261a72cb07a6815c69",
    "status" : 1
}

Laravel:

Model:

Employee:

<?php
namespace App\Models;

use Jenssegers\Mongodb\Eloquent\Model as Eloquent;

class Employee extends Eloquent {

    protected $collection = 'employee';
    protected $primaryKey = '_id';

    public function tasks()
    {
        return $this->hasMany('App\Models\Task');
    }
}

Task:

<?php
namespace App\Models;

use Jenssegers\Mongodb\Eloquent\Model as Eloquent;

class Task extends Eloquent {

    protected $collection = 'task';
    protected $primaryKey = '_id';

    public function employees()
    {
        return $this->belongsToMany('App\Models\Employee');
    }
}   

Controller:

public function EmployeeData($data)
{
    $employee= Employee::find('586ca8c71a72cb07a681566d')->tasks;
    echo "<pre>";
    print_r($employee);
}

When I want to see task against employee it shows me below error:

Illuminate\Database\Eloquent\Collection Object
(
    [items:protected] => Array
        (
        )

)

How can I fix this?

via Chebli Mohamed