No reverse match for rest_framework namespace
The error for a very strange reason shows when accessing these URLs:
https://github.com/swcarpentry/amy/blob/develop/api/urls.py#L57

I wasn't able to get rid of it; it's not being used at all, so maybe it should be removed…?

diff --git a/api/urls.py b/api/urls.py
index 4eecbc2b..ad8aa1df 100644
--- a/api/urls.py
+++ b/api/urls.py
@@ -52,10 +52,4 @@ urlpatterns = [
     url('^', include(todos_router.urls)),
 ]
 
-# for login-logout functionality
-urlpatterns += [
-    url(r'^api-auth/',
-        include('rest_framework.urls', namespace='rest_framework')),
-]
-
 urlpatterns = format_suffix_patterns(urlpatterns)  # allow to specify format
['api/urls.py']