Error in larabel 5.1. method save

Error while trying to save logs in larabel 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. Thanks

 <?php

namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Grupo;

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');
        $grupo = new Grupo();


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

        return view('grupos.agregar_grupo');
    }

}

this error this error image

via Chebli Mohamed