Laravel 5.1出错。 方法保存

Error while trying to save logs in Laravel 5.1. The code and screenshot of the error shown below. I do not know how to solve them if I appeal to you, I look forward to your help.

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Grup;
use App\Http\Requests;
use App\Http\Controllers\Controller;

class ControllerGrupos extends Controller
{
    public function agregar_Grupo(Requests $request)
    {
        $nom = $request->get('name');

        $des   = $request->get('descrition');
        $grup = new Grup();


        $grup->nombre      = $nom;
        $grup->descripcion = $des;
        $grup->save();

        return view('grupos.agregar_grupo');
    }

}

Error