Run JupyterHub master!

We want to get access to the eventlogging feature
(jupyterhub/jupyterhub#2698) and the
user-redirect customization
(jupyterhub/jupyterhub#2790?)

This is a little scary, but there is enough testing that I feel
this should be fine.

images/hub/Dockerfile

@@ -8,7 +8,7 @@ RUN apt update && apt install --yes curl python
 RUN curl -O https://dl.google.com/dl/cloudsdk/channels/rapid/downloads/google-cloud-sdk-245.0.0-linux-x86_64.tar.gz && \
     tar xzf google-cloud-sdk-245.0.0-linux-x86_64.tar.gz && \
     mv google-cloud-sdk /usr/local/google-cloud-sdk && \
-    rm google-cloud-sdk-245.0.0-linux-x86_64.tar.gz 
+    rm google-cloud-sdk-245.0.0-linux-x86_64.tar.gz
 
 ENV PATH /usr/local/google-cloud-sdk/bin:${PATH}
 RUN gcloud components install kubectl
@@ -19,4 +19,13 @@ RUN python3 -m pip install --no-cache /srv/sparklyspawner
 COPY canvasauthenticator /srv/canvasauthenticator
 RUN python3 -m pip install --no-cache /srv/canvasauthenticator
 
+# Install JupyterHub from master!
+# This is scary-ish, but we need JupyterHub master for the analytics / user-redirect work
+# npm's dependencies seem to be not well specified in default apt repositories, so we need to explicitly add them
+RUN apt-get update --yes --quiet && \
+    apt-get install --yes --no-install-recommends nodejs-dev node-gyp libssl1.0-dev npm && \
+    rm -rf /var/lib/apt/lists/*
+
+RUN python3 -m pip install git+https://github.com/jupyterhub/jupyterhub.git@2847c3a90c241b212b89aef6181b6da687948a03
+
 USER ${NB_USER}