The current URL, app/, didn't match any of these

I think you have edited the wrong file when trying to change the root url config.

Make sure you are editing the root url config in mysite/mysite/urls.py (the directory containing settings.py) not mysite/urls.py (the directory containing manage.py).

As general advice, install the latest release, currently 1.9. Don't use 1.10, which is under development. Make sure that you are following the tutorial for 1.9, because the tutorial changes for different versions. For example, your mysite/urls.py doesn't match the tutorial for 1.9, as the urlpatterns should be:

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

In settings.py you have a setting name INSTALLED_APPS-

Adds you app i.e. polls to it.

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    ....
    'polls',
]