Errors in custom authentication in laravel 5.2

i create a new table with name of students

public function up()
    {
        Schema::create('students', function (Blueprint $table) {
            //   $table->increments('id');
            $table->engine = 'InnoDB';

            $table->string('roll_no');
            $table->string('name');
            $table->string('father_name');
            $table->string('address');
            $table->string('cnic');
            $table->string('phone_no');
            $table->string('father_phone_no');
            $table->string('email')->unique();
            $table->string('password');
//            $table->string('dept_id');
            $table->timestamps();

            $table->primary('roll_no');
//            $table->foreign('dept_id')->references('dept_id')->on('departments')->onDelete('cascade');
        });
    }

then i create a student model that is empty

class student extends Authenticatable
{
    //
}

then i make changes in my auth.php file

<?php

return [


    'defaults' => [
        'guard' => 'web',
        'passwords' => 'users',
    ],

    'guards' => [
        'web' => [
            'driver' => 'session',
            'provider' => 'users',
        ],
        'student' => [
            'driver' => 'session',
            'provider' => 'students',
        ],

        'api' => [
            'driver' => 'token',
            'provider' => 'users',
        ],
    ],

    'providers' => [
        'users' => [
            'driver' => 'eloquent',
            'model' => App\User::class,
        ],
        'student' => [
            'driver' => 'eloquent',
            'model' => App\student::class,
        ],
    ],

    'passwords' => [
        'users' => [
            'provider' => 'users',
            'email' => 'auth.emails.password',
            'table' => 'password_resets',
            'expire' => 60,
        ],
        'students' => [
            'provider' => 'students',
            'email' => 'student.auth.emails.password',
            'table' => 'password_resets',
            'expire' => 60,
        ],
    ],

];

then i add a middleware RedirectifNotStudent

public function handle($request, Closure $next, $guard = 'student')
    {
        if (!Auth::guard($guard)->check()) {
            return redirect('/student/login');
        }

        return $next($request);
    }

then i add this line to kernel.php file

'student' => \App\Http\Middleware\RedirectIfNotstudent::class,

after that i add a login, logout, registration function in that directory StudentAuth/AuthController

    protected $redirectTo = '/student';
        protected $guard = 'student';
public function showLoginForm()
    {
        if (Auth::guard('student')->check())
        {
            return redirect('/student');
        }

        return view('student.auth.login');
    }

    public function showRegistrationForm()
    {
        return view('student.auth.register');
    }

    public function resetPassword()
    {
        return view('student.auth.passwords.email');
    }

    public function logout(){
        Auth::guard('student')->logout();
        return redirect('/student/login');
    }

After that i add Employee controller in Student/Employee like this

    class Employee extends Controller
{
    public function __construct(){
        $this->middleware('student');
    }

    public function index(){
        return view('Student.home');
    }
}

this my route file

    Route::get('/student/login','StudentAuth\AuthController@showLoginForm');
Route::post('/student/login','StudentAuth\AuthController@login');
Route::get('/student/password/reset','StudentAuth\PasswordController@resetPassword');

Route::group(['middleware' => ['student']], function () {
    //Login Routes...
    Route::get('/student/logout','StudentAuth\AuthController@logout');

    // Registration Routes...
    Route::get('student/register', 'StudentAuth\AuthController@showRegistrationForm');
    Route::post('student/register', 'StudentAuth\AuthController@register');

    Route::get('/student', 'Student\Employee@index');
});



Route::group(['middleware' => 'web'], function () {
//    Route::auth();
    Route::get('/home', 'HomeController@index');

builtin authentication is working fine but i want another for student and this error is occur

Authentication user provider [] is not defined.