Eloqunet Model: Define on-to-one relationship using flag on child table

I have 2 tables vendors and partners

vendors table only stores the name of some company and partners table store users who work for some company. So the structure is somethign like this:

vendors

|  id  |   name        |
+------+---------------+
|   1  |   Vendor-1    |
|   2  |   Vendor-2    |
|   3  |   Vendor-3    |

Partners

| id | user_name  | password  |vendor_id |  is_owner  |  is_admin  | is_technitian |
+----+------------+-----------+----------+------------+------------+---------------+
| 1  | abc        | ^&ASKJHA  |    1     |    1       |      1     |      0        | 
| 2  | def        | ^&ASKJHA  |    2     |    1       |      1     |      0        |
| 3  | ghi        | ^&ASKJHA  |    1     |    0       |      1     |      0        |
| 4  | jkl        | ^&ASKJHA  |    3     |    1       |      1     |      0        |
| 5  | mno        | ^&ASKJHA  |    1     |    0       |      0     |      1        |
| 6  | pqr        | ^&ASKJHA  |    2     |    0       |      1     |      0        |
| 7  | stu        | ^&ASKJHA  |    1     |    0       |      0     |      1        |
| 8  | vwx        | ^&ASKJHA  |    2     |    0       |      0     |      1        |
| 9  | yz         | ^&ASKJHA  |    3     |    0       |      0     |      1        |

So as you can see above that One partner is the owner of any vendor and rest of them work as employees for the vendor.

I am working with Eloquent ORM and i have already defined Models for both Partner and vendor. I want to add an owner method in the Vendor Model so i can directly access the owner for any vendor Object. What i want to know is how do i relate this in my model defination. Is it do-able or do i need to make some changes in my database structure ?

class Vendor extends Model{

  /**
   * Get all the users for this vendor
   */
  public function users(){
     $this->hasMany(Partner::class);
  }

  public function owner(){
    // how do i relate one owner from partner model who has is_owner == 1
  }
}

via Angry Coder