Fix permissions on /opt/install

Dockerfile

@@ -15,7 +15,9 @@ RUN apt-get -y update \
 # apt-get may result in root-owned directories/files under $HOME
 RUN chown -R $NB_UID:$NB_GID $HOME
 
-USER $NB_USER
 ADD . /opt/install
+RUN fix-permissions /opt/install
+
+USER $NB_USER
 RUN cd /opt/install && \
    conda env update -n base --file environment.yml