django-rest-framework 出现 TemplateDoesNotExist

# settings.py
INSTALLED_APPS = [
    rest_framework
]

# urls.py
class StorySerializer(serializers.HyperlinkedModelSerializer):
class Meta:
    model = Story
    fields = ('name', 'description')

class StoryViewSet(viewsets.ModelViewSet):
    queryset = Story.objects.all()
    serializer_class = StorySerializer


router = routers.DefaultRouter()
router.register('stories', StoryViewSet)

urlpatterns = [
    url(r'^', include(router.urls)),
    url(r'^api/', include('rest_framework.urls', namespace='rest_framework'))
]

# 浏览器
http://localhost:8000

TemplateDoesNotExist at /
rest_framework/api.html
Request Method: GET
Request URL:    http://localhost:8000/
Django Version: 1.9
Exception Type: TemplateDoesNotExist
Exception Value: rest_framework/api.html
Exception Location: /usr/local/lib/pypy/site-packages/django/template/loader.py in get_template, line 43
Python Executable:  /usr/local/lib/pypy/bin/pypy
Python Version: 2.7.10
Python Path:    
    ['/Users/tracy/Desktop/pypy/todo',
     '/Users/tracy/Desktop/pypy/todo',
     '/usr/local/lib/pypy/lib_pypy/__extensions__',
     '/usr/local/lib/pypy/lib_pypy',
     '/usr/local/lib/pypy/lib-python/2.7',
     '/usr/local/lib/pypy/lib-python/2.7/lib-tk',
     '/usr/local/lib/pypy/lib-python/2.7/plat-darwin',
     '/usr/local/lib/pypy/lib-python/2.7/plat-mac',
     '/usr/local/lib/pypy/lib-python/2.7/plat-mac/lib-scriptpackages',
     '/usr/local/lib/pypy/site-packages']
Server time:    Wed, 23 Dec 2015 13:28:33 +0000

Template-loader postmortem

Django tried loading these templates, in this order:

Using engine django:
django.template.loaders.filesystem.Loader: /Users/tracy/Desktop/pypy/todo/templates/rest_framework/api.html (Source does not exist)