django admin unreachable

404.html

GET http://localhost:8000/admin

Page not found (404)
Request Method:	GET
Request URL:	http://localhost:8000/admin
Using the URLconf defined in mysite.urls, Django tried these URL patterns, in this order:

^ ^$ [name='index']
^admin/
^static\/(?P<path>.*)$
The current path, admin, didn't match any of these.

urls.py

from django.conf import settings
from django.conf.urls import include, url
from django.contrib import admin
from django.contrib.staticfiles.urls import staticfiles_urlpatterns

urlpatterns = [
    url(r'^', include('polls.urls')),
    url(r'^admin/', admin.site.urls)
]

# Only serve static files from Django during development
# Use Google Cloud Storage or an alternative CDN for production
if settings.DEBUG:
    urlpatterns += staticfiles_urlpatterns()

django 2.0 uses path, do

from django.conf import settings
from django.contrib import admin
from django.urls import include, path
from django.contrib.staticfiles.urls import staticfiles_urlpatterns

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('polls.urls')),
]

# Only serve static files from Django during development
# Use Google Cloud Storage or an alternative CDN for production
if settings.DEBUG:
    urlpatterns += staticfiles_urlpatterns()

and open http://localhost:8000/admin

you should also update polls/urls.py but I'll leave that as an exercise for the reader, read the new syntax in django 2.0 at https://docs.djangoproject.com/en/2.0/intro/tutorial01/

also update middleware settings https://stackoverflow.com/questions/48100144/django-admin-error-wsgirequest-object-has-no-attribute-user/48100301#48100301