Can i ignore unique value when update record laravel 5.8?

Question

I need to ignore unique validation on update I created Request file named "AskQuestionRequest" has rules :

 public function rules()
    {
        return [
            'title'=>'required|max:255|unique:questions',
            'body'=>'required',
        ];
    }

when I update body record i get The "title has already been taken." anyone can help !