diff --git a/docker-images/i2b2-web/Dockerfile b/docker-images/i2b2-web/Dockerfile
index bbd60cd..777f6dc 100644
--- a/docker-images/i2b2-web/Dockerfile
+++ b/docker-images/i2b2-web/Dockerfile
@@ -1,78 +1,78 @@
 FROM debian:jessie-backports
 
 # variables
 ARG I2B2_DOMAIN_NAME_ARG="i2b2demo"
 ENV I2B2_VERSION="v1.7.08a" \
     I2B2_WEB_DIR="/opt/i2b2-webclient" \
     SHRINE_SRC_DIR="/opt/shrine-src" \
     SHRINE_VERSION="fork/1.22.8-medco" \
     I2B2_DOMAIN_NAME="$I2B2_DOMAIN_NAME_ARG" \
     LIGHTTPD_WEB_ROOT="/var/www/html" \
     DB_PASSWORD="pFjy3EjDVwLfT2rB9xkK" \
     CONF_DIR="/opt/medco-configuration"
 
 # requirements
 RUN echo "deb http://httpredir.debian.org/debian jessie-backports main contrib non-free" >> /etc/apt/sources.list && \
     apt-get -y update && \
     apt-get -y install lighttpd php5-cgi curl libcurl3 php5-common php5-cli php5-curl git php5-pgsql php5-mysql wget tar && \
     apt-get -y -t jessie-backports install postgresql-client && \
     apt-get -y clean && \
     lighttpd-enable-mod fastcgi-php ssl
 
 RUN mkdir -p "$I2B2_WEB_DIR" "$SHRINE_SRC_DIR" && \
     chgrp -R www-data /opt /etc/lighttpd && \
     chmod -R g+rwx /opt /etc/lighttpd && \
     chown -R www-data:www-data "$LIGHTTPD_WEB_ROOT" && \
     chmod -R +rx "$LIGHTTPD_WEB_ROOT" && \
     install -d -o www-data -g www-data -m 0750 "/var/run/lighttpd"
 USER www-data
 
 # phpPgAdmin
 WORKDIR "$LIGHTTPD_WEB_ROOT"
 RUN wget http://downloads.sourceforge.net/phppgadmin/phpPgAdmin-5.1.tar.gz?download && \
     tar xvzf phpPgAdmin-5.1.tar.gz?download && \
     rm phpPgAdmin-5.1.tar.gz\?download && \
     mv phpPgAdmin-5.1 phppgadmin && \
     sed -i "s/'host'] = ''/'host'] = 'i2b2-database'/" phppgadmin/conf/config.inc.php && \
     sed -i "s/ = 'PostgreSQL'/ = '$I2B2_DOMAIN_NAME PostgreSQL Server'/" phppgadmin/conf/config.inc.php && \
     sed -i "s/'extra_login_security'] = true/'extra_login_security'] = false/" phppgadmin/conf/config.inc.php && \
     sed -i "/\$cmd = \$exe/c\$cmd = \$exe;" phppgadmin/dbexport.php
 
 # phpMyAdmin
 RUN wget https://files.phpmyadmin.net/phpMyAdmin/4.7.5/phpMyAdmin-4.7.5-english.tar.gz && \
     tar xvzf phpMyAdmin-4.7.5-english.tar.gz && \
     rm phpMyAdmin-4.7.5-english.tar.gz && \
     mv phpMyAdmin-4.7.5-english phpmyadmin && \
     cp phpmyadmin/config.sample.inc.php phpmyadmin/config.inc.php && \
     sed -i "s#localhost#shrine-database#g" phpmyadmin/config.inc.php && \
     sed -i "s#\$cfg['blowfish_secret'] = '';#\$cfg['blowfish_secret'] = 'ac28vb01sfv0vcs1v96fv06fv0df62fv';#g" phpmyadmin/config.inc.php
 
 # download i2b2 webclient
 WORKDIR "$I2B2_WEB_DIR"
 RUN git clone https://github.com/i2b2/i2b2-webclient.git . && \
     git checkout tags/$I2B2_VERSION
 
 # download shrine webclient
 WORKDIR "$SHRINE_SRC_DIR"
 RUN git clone https://c4science.ch/source/shrine-medco.git . && \
     git checkout $SHRINE_VERSION && \
     cp "$I2B2_WEB_DIR"/index.php "$SHRINE_SRC_DIR"/shrine-webclient/src/main/html/
 
 # copy clients
 RUN cp -R "$I2B2_WEB_DIR" "$LIGHTTPD_WEB_ROOT/i2b2-admin" && \
     cp -R "$I2B2_WEB_DIR" "$LIGHTTPD_WEB_ROOT/i2b2-client" && \
     cp -R "$SHRINE_SRC_DIR/shrine-webclient/src/main/html" "$LIGHTTPD_WEB_ROOT/shrine-client"
 
 # copy and apply settings
 ARG NODE_IDX_ARG="0"
 ENV NODE_IDX="$NODE_IDX_ARG"
 USER root
 COPY i2b2-web-writeconfig.sh shrine-webclient-update.sh /opt/
 RUN chgrp www-data /opt/*.sh && \
     chmod g+rwx /opt/*.sh && \
     sleep 1 && \
-    su -c "/bin/bash -c /opt/i2b2-web-writeconfig.sh" www-data
+    su - "www-data" -s /bin/bash -c "/opt/i2b2-web-writeconfig.sh"
 
 # run
 EXPOSE 80
 CMD ["lighttpd", "-D", "-f", "/etc/lighttpd/lighttpd.conf"]