Update Dockerfile

Dockerfile

@@ -6,3 +6,7 @@ FROM renku/singleuser:0.2.0
 # install the python dependencies
 COPY requirements.txt /tmp/requirements.txt
 RUN pip install -r /tmp/requirements.txt
+
+RUN $CONDA_DIR/envs/renku/bin/pip install -U -e git+https://github.com/SwissDataScienceCenter/renku-python.git#egg=renku
+
+RUN sudo apt-get install -y poppler-utils