urls.py

from django.conf.urls import url
from . import views

urlpatterns = [
    # /music/
    url(r'^$', views.index, name='index'), # r - regular exp., ^ - start, $ - end. this is for /music/

    # /muisic/71/
    url(r'^(?P<album_id>[0-9]+)/$', views.detail, name='detail'),
]