models.py foreign keys
# django 1.1 d = models.ForeignKey(Board, related_name='topics') # django 2 d = models.ForeignKey(Board, related_name='topics', on_delete=models.PROTECT)
No module named django.core.urlresolvers
# django 1.1 from django.core.urlresolvers import reverse # django 2 from django.urls import reverse
urls.py
The new path() syntax in Django 2.0 does not use regular expressions. You want something like:
path('<int:album_id>/', views.detail, name='detail'),
If you want to use a regular expression, you can use re_path().
re_path(r'^(?P<album_id>[0-9])/$', views.detail, name='detail'),
The old url() still works and is now an alias to re_path, but it is likely to be deprecated in future.
url(r'^(?P<album_id>[0-9])/$', views.detail, name='detail'),