Adding movies to the cart

To allow the addition of movies to the cart, we will follow the next steps:

1. Configure the add_to_cart URL.
2. Define the add_to_cart function.
3. Update the movies.show template.

Configuring the add_to_cart URL

In /cart/, create a new file called urls.py. This file will contain the path regarding the URLs of the cart app. For now, fill it in with the following:

from django.urls import path
from . import views
urlpatterns = [
    path('<int:id>/add/', views.add, name='cart.add'),
]

We added a new path called cart/<int:id>/add (remember that the project-level URLs file defined a /cart prefix for this file). The <int:id> part indicates that this path expects an integer value to be passed from the URL and that the integer value will be associated with a variable named id. The id variable will be used to identify which movie we want to add to the cart. For example, the cart/1/add...