Update dockerfile

Dockerfile

@@ -1,5 +1,20 @@
 FROM andrewosh/binder-base
 
+ENV NB_USER jovyan
+ENV NB_UID 1000
+ENV HOME /home/${NB_USER}
+
+RUN adduser --disabled-password \
+    --gecos "Default user" \
+    --uid ${NB_UID} \
+    ${NB_USER}
+
+# Make sure the contents of our repo are in ${HOME}
+COPY . ${HOME}
+USER root
+RUN chown -R ${NB_UID} ${HOME}
+USER ${NB_USER}
+
 USER root
 
 # Add Julia dependencies