public function destroy($id)
{
$cover = Cover::find($id);
$cover->delete();
flash()->success('删除成功');
return redirect()->back();
}
public function update(array $data, $id)
{
$cover = Cover::find($id);
$cover->name = $data['name'];
$cover->cover_url = $data['cover_url'];
$cover->display = $data['display'];
$cover->save();
return $cover;
}