Add sorting support for dot notation column names

[shemgp]

Sorting was not working. I think it's because sortBy only works with arrays. Here's a way to make sorting work even for dot notation columns. Eg. User->post->subject with column User.post.name.

[aginev]

Hello @shemgp,

What is the purpose of this pull requests? If you are trying to do actual search take a look at: https://github.com/aginev/search-filters The purpose of this package is only to display the table structured data, not actually to filter the results...

If using the search filters, take a look at it's readme and you can filter results like so:

$users = $userModel->with(['roles'])->filter(\Request::input('f', []))->orderBy('id', 'desc')->paginate(12);
$grid = new \Datagrid($users, \Request::input('f'));

// Add some columns to datagrid
$grid
    ->setColumn('id', '#', [
        'sortable'    => true,
        'has_filters' => true,
    ])
    ->setColumn('name', trans('admin/users.name'), [
        'sortable'    => true,
        'has_filters' => true,
    ])
    ->setColumn('role_id', trans('admin/users.role'), [
        'sortable'    => false,
        'has_filters' => true,
        'filters'     => Role::all()->pluck('name', 'id'),
        'wrapper'     => function ($value, $row) {
            return $row->getData()->roles->first()->name;
        },
    ])
    ->setColumn('email', trans('admin/users.email'), [
        'sortable'    => true,
        'has_filters' => true,
        'wrapper'     => function ($value, $row) {
            return '<a href="mailto:' . $value . '" target="_blank">' . $value . '</a>';
        },
    ])
    ->setColumn('created_at', trans('admin/users.created_at'), [
        'sortable'    => true,
        'has_filters' => true,
    ])
    ->setColumn('updated_at', trans('admin/users.updated_at'), [
        'sortable'    => true,
        'has_filters' => true,
    ]);

$grid->setActionColumn([
    'wrapper' => function ($value, $row) {
        return '<a href="' . action('Admin\UsersController@edit', $row->id) . '" class="btn btn-xs btn-success" title="' . trans('admin/users.edit_btn') . '"><i class="fa fa-pencil"></i></a>';
    },
]);

[shemgp]

I am using datagrid for the view part of the Infyom CRUD (InfyOmLabs/laravel-generator#295). I didn't know that there was aginev/search-filters so I thought the code had a bug as it wasn't searching nor filtering.