public function show($slug)
{
$book = $this->bookRepo->getBySlug($slug);
$this->checkOwnablePermission('book-view', $book);
$bookChildren = $this->bookRepo->getChildren($book);
Views::add($book);
$this->setPageTitle($book->getShortName());
return view('books/show', ['book' => $book, 'current' => $book, 'bookChildren' => $bookChildren]);
}