Specify exact hash in dockerfile
This lets us bump and rebuild it when necessary
FROM python:3.6-alpine@sha256:00320c25fa72df54c7ef0181c9e55f59f58b1facb943cb825e4c65fb572ac74b
-# FIXME: temporary ref pending binderhub#110
-RUN pip install --no-cache-dir https://github.com/jupyterhub/binderhub/archive/master.zip
+RUN pip install --no-cache-dir \
+ https://github.com/jupyterhub/binderhub/archive/1e3dd8e.zip
ADD binderhub_config.py /etc
WORKDIR /etc
