added path for edit book page

lancedamalerio_reading/bookshelf/urls.py

 from django.urls import path
 from .views import (HomeView, BookListView, BookDetailView, AuthorListView, AuthorDetailView, 
-                    BookCreateView, AuthorCreateView)
+                    BookCreateView, AuthorCreateView, BookUpdateView)
 
 #url for bookshelf
 
@@ -9,6 +9,7 @@ urlpatterns = [
     path('books/', BookListView.as_view(), name = 'book-list'),
     path('books/<int:pk>/details', BookDetailView.as_view(), name = 'book-details'),
     path('books/add/', BookCreateView.as_view(), name="new-book"),
+    path('books/<int:pk>/edit', BookUpdateView.as_view(), name="update-book"),
     path('authors/', AuthorListView.as_view(), name = 'author-list'),
     path('authors/<int:pk>/details', AuthorDetailView.as_view(), name = 'author-details'),
     path('authors/add/', AuthorCreateView.as_view(), name="new-author"),