Cannot update user

I just created a user edit page, but when I submit it doesn't change.

This is my link to edit:

<a href="{{route('userEdit', $user->id)}}" class="text-primary"><i class="fa fa-edit"></i></a>

This is my route:

Route::group(['prefix' => 'admin/', 'middleware' => ['role:developer|admin']], function()
{
    Route::get('dashboard', 'AdminController@dashboard')->name('adminDashboard');

    Route::get('manage/user/index', 'AdminController@userIndex')->name('userIndex');
    Route::get('manage/user/create', 'AdminController@userCreate')->name('userCreate');
    Route::post('manage/user/store', 'AdminController@userStore')->name('userStore');
    Route::get('manage/user/edit/{id}', 'AdminController@userEdit')->name('userEdit');
    Route::post('manage/user/update/{id}', 'AdminController@userUpdate')->name('userUpdate');
});

This is my controller:

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\User;
use App\Role;
use File;

class AdminController extends Controller
{
    public function __construct()
    {
        $this->middleware('auth');
        $this->middleware(['role:developer|admin']);
    }

    public function dashboard()
    {
        return view('admin.dashboard');
    }

    public function userIndex()
    {
        $users = User::orderBy('id', 'desc')->paginate(10);
        return view('admin.manage.user.index', compact('users'));
    }

    public function userEdit($id)
    {
        $users   = User::find($id);
        $roles  = Role::all();
        return view('admin.manage.user.edit', compact('users', 'roles'));
    }

    public function userUpdate(Request $request, $id)
    {
        // Menyiapkan data gambar yang diupload ke variabel $file
        $file_name = $request->hidden_image;
        $file = $request->file('file');
        if($file !='')
        {
            $this->validate($request,[
                'name'      =>  'required|alpha|max:255',
                'email'     =>  'required|email|unique:users',
                'password'  =>  'required',
                'file'      =>  'required|file|image|mimes:jpeg,jpg,png|max:1048'
            ]);

            // Menyiapkan data gambar yang diupload ke variabel $file
            $file_name  = time()."_".$file->getClientOriginalName();

            // Isi dengan nama folder tempat kemana file diupload
            $upload_directory = 'p_users';
            $file->move($upload_directory, $file_name);

            // Hapus file
            $gambar = User::where('id',$id)->first();
            File::delete(public_path('p_user/'.$gambar->file));
        }
        else
        {
            $this->validate($request,[
                'name'      =>  'required|alpha|max:255',
                'email'     =>  'required|email|unique:users',
                'password'  =>  'required'
            ]);
        }

        $users = User::find($id);
        $users->name     =   $request->name;
        $users->email    =   $request->email;
        $users->password =   bcrypt($request->password);
        $users->file     =   $file_name;

        $users->save();
        $users->syncRoles(explode(',', $request->roles));
        return redirect()->route('userIndex');
    }
}

This is my edit form:

<!-- Form start -->
<form action="{{route('userUpdate', $users->id)}}" method="post" enctype="multipart/form-data">
	{{csrf_field()}}
	<div class="box-body">
		<div class="row">
			<div class="col-md-3">
				<div class="form-group">
					<label>Fullname</label>
					<input type="text" value="{{$users->name}}" name="name" class="form-control">
				</div>
			</div>
			<div class="col-md-3">
				<div class="form-group">
					<label>Email address</label>
					<input type="email" value="{{$users->email}}" name="email" class="form-control">
				</div>
			</div>
			<div class="col-md-3">
				<div class="form-group">
					<label>Password</label>
					<input type="password" value="{{$users->password}}" name="password" class="form-control">
				</div>
			</div>
			<div class="col-md-3">
				<div class="form-group">
					<label>Roles</label>
					<select class="form-control" name="roles">
						<option disabled selected>Choose</option>
						@foreach ($roles as $role)
							<option value="{{$role->id}}" {{$role->id == $role->id ? 'selected' : ''}}>{{$role->display_name}}</option>
						@endforeach
					</select>
				</div>
			</div>
			<div class="col-md-3">
				<div class="form-group">
					<label>Profile Picture</label>
					<div>
						<img src="{{ url('p_users/'.$users->file) }}" width="100">
					</div>
					<input type="file" name="file" class="form-control-file">
					<input type="hidden" name="hidden_image" value="{{$users->file}}">
				</div>
			</div>
		</div>
	</div>
	<div class="box-footer">
		<button type="submit" class="btn btn-primary">Save change</button>
	</div>
</form>