Convert the API URL system from an App based one

to a resource based one.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/folders/urls.py

@@ -60,7 +60,7 @@ api_urls = [
     ),
     url(r'^folders/$', APIFolderListView.as_view(), name='folder-list'),
     url(
-        r'^document/(?P<pk>[0-9]+)/folders/$',
+        r'^documents/(?P<pk>[0-9]+)/folders/$',
         APIDocumentFolderListView.as_view(), name='document-folder-list'
     ),
 ]