How to update value in User Table in laravel 5.1

I have an issue I cannot update my user table . I don't know where he problem is.Whenever I submit my updated info it cannot updated. It Does not show any error. But the table is not updated. Please Help me guys. My Controller is

public function getUpdate() {

        $profile = Auth::user();
        return view('admin.article.edit')
        ->with('profile',$profile);
    }

    public function postUpdate(Request $request ) {
$profile = Auth::user();

        $this->validate($request, [
            'name' => 'required|max:120',
            'username' => 'required|max:80',
            'email' => 'required',
            'password' => 'required'
            ]);

         // save users table
        $profile = Auth::user();
        // $user = new App\User;
        $profile->name = $request->input('name');
        $profile->email = $request->input('email');
        $profile->username = $request->input('username');
        $profile->password = $request->input('password');
        $profile->update();
}

My edit.blade.php page is

<?php $active="profile"; ?>
@extends('admin.dashboard')
@section('content')
  <!-- Content Wrapper. Contains page content -->
  <div class="content-wrapper">
    <!-- Content Header (Page header) -->
    <section class="content-header">
      <h1>
        User Profile
      </h1>
      <ol class="breadcrumb">
        <li><a href="#"><i class="fa fa-dashboard"></i> Home</a></li>
        <li class="active">User profile</li>
      </ol>
    </section>

<!-- Main content -->
    <section class="content">
      <div class="row">
        <!-- left column -->
        <div class="col-md-10">
          <!-- general form elements -->
          <div class="box box-primary">
            <div class="box-header with-border">
              <h3 class="box-title">Quick Example</h3>
            </div>
            <!-- /.box-header -->
            <!-- form start -->
            <form action="" role="form" method="post" enctype="multipart/form-data">
              <div class="box-body">
                <div class="form-group">
                  <label for="name">Name</label>
                  <input type="text" class="form-control" name="name" id="name"  value="">
                </div>
                <div class="form-group">
                  <label for="username">User Name</label>
                  <input type="text" class="form-control" name="institute" id="institute"  value="">
                </div>
</div>
              <!-- /.box-body -->

              <div class="box-footer">
                <button type="submit" class="btn btn-primary">Submit</button>
                <input type="hidden" name="_token" value="">
                <input type="hidden" name="id" value="">
              </div>
            </form>
          </div>
          <!-- /.box -->

        </div>
        <!--/.col (left) -->
      </div>
      <!-- /.row -->
    </section>
    <!-- /.content -->
@endsection  

My route file is

Route::get('/profile/edit', [
                    'uses' => 'ProfileController@getUpdate',
                    'as' => 'edit'
            ]);

        Route::post('profile/update', [
                    'uses' => 'ProfileController@postUpdate',
                    'as' => 'update'
            ]);

via Chebli Mohamed