如何在Eloquent中包含属于父模型的子模型中的一列或多列？

In User Model :

public function role(){

    return $this->hasOne('App\Model\Roles','id','role_id');

}

In Roles Model:

public function user(){

    return $this->belongTo('App\Model\Users');

}

In method :

$query = Users::where('id', $id)->get();

What i get (in JSON):

[{"id":2,"user_name":"hazardgeek","user_email":"nwasuper@example.com","user_phone":"*******","user_password":"*********","remember_token":"*****","role_id":2}]

What i actually want:

i want the role_title column from the Roles model, not role_id from Users table. Like this, ......user_password":"thesupernwa","remember_token":null,"role_title":"customer"}]

How can i achieve this?? Thank you.

In User.php Model

public function User(){
     protected $appends = ['role_title'];

     public function getRoleTitleAttribute(){
          $role = $this->getRelation('role');
          return !empty($role) ? $this->role->role_title : null;
     }
}

I ended up using a raw queries to retrieve the right response

return DB::table('ctr_user')
            ->select('ctr_user.id AS user_id','user_name','user_email','user_phone','user_password','remember_token','ctr_role.role_title AS title')
            ->rightJoin('ctr_role', 'ctr_role.id','=','ctr_user.role_id')
            ->where('ctr_user.id','=',$id)
            ->get();

response return by this raw queries is exactly response I need using Eloquent.

But still how?