Show bookshelves that a book belongs to on a book view

Closes #1598

app/Entities/Repos/EntityRepo.php

@@ -413,6 +413,17 @@ class EntityRepo
         return collect($tree);
     }
 
+
+    /**
+     * Get the bookshelves that a book is contained in.
+     * @param Book $book
+     * @return \Illuminate\Database\Eloquent\Collection|static[]
+     */
+    public function getBookParentShelves(Book $book)
+    {
+        return $this->permissionService->enforceEntityRestrictions('shelf', $book->shelves())->get();
+    }
+
     /**
      * Get the child items for a chapter sorted by priority but
      * with draft items floated to the top.

app/Http/Controllers/BookController.php

@@ -150,6 +150,7 @@ class BookController extends Controller
         $this->checkOwnablePermission('book-view', $book);
 
         $bookChildren = $this->bookRepo->getBookChildren($book);
+        $bookParentShelves = $this->bookRepo->getBookParentShelves($book);
 
         Views::add($book);
         if ($request->has('shelf')) {
@@ -161,6 +162,7 @@ class BookController extends Controller
             'book' => $book,
             'current' => $book,
             'bookChildren' => $bookChildren,
+            'bookParentShelves' => $bookParentShelves,
             'activity' => Activity::entityActivity($book, 20, 1)
         ]);
     }