Merge branch 'django' into jupyterhub_2019

The branc cannot run job, this looks related to code already updated in the django branch.

django/Dockerfile

@@ -10,7 +10,7 @@ RUN apt-getq update && apt-getq install	\
   python-mysqldb python3-crypto gunicorn3 python3-redis python-mysqldb \
   python3-crypto python3-natsort python3-aiohttp python3-aioredis supervisor	\
   python3-ipy python3-django-taggit python3-iso8601 python3-robot-detection	\
-  python3-sqlparse
+  python3-sqlparse python3-django-extensions python3-pydotplus
 
 COPY requirements.txt /tmp/
 RUN cd /tmp && pip3 install -r requirements.txt && rm requirements.txt

django/config/settings.py

@@ -115,6 +115,7 @@ THIRD_PARTY_APPS = [
     'allauth.socialaccount',
     'allauth.socialaccount.providers.gitlab',
     'taggit',
+    'django_extensions',
 ]
 LOCAL_APPS = [
     'main',

django/docs/generate_models_png.sh

+#! /bin/bash
+
+# TODO: the command should be placed in the Makefile or an official doc.
+# It should be ran in the django container.
+# cf https://django-extensions.readthedocs.io/en/latest/graph_models.html
+python3 ./manage.py graph_models --all-applications --group-models --output allgo_model.png