Laravel 5.1 File not deleting from folder

I want to delete a pdf file form my database as well as my public/uploads folder. It is deleting from the database but not from my public folder.

This is my controller:

 public function deleteArticle($id) {
    $article = Article::findOrFail($id);

     File::delete($article->document);
        $article->delete();
    return redirect()->back();
   }

via Chebli Mohamed