diff --git a/build/Dockerfile b/build/Dockerfile
index 456cccc..f1ee765 100644
--- a/build/Dockerfile
+++ b/build/Dockerfile
@@ -49,10 +49,10 @@ COPY webroot /usr/share/nginx/html/
 EXPOSE 80 443
 
 # clean-up permissions and run as www-docker user
-RUN chown -R ${USER}:${USER} /usr/share/nginx/html \
+RUN chown -R www-docker:www-docker /usr/share/nginx/html \
     && find /usr/share/nginx/html -type d -exec chmod 775 {} \; \
     && find /usr/share/nginx/html -type f -exec chmod 664 {} \; \
-    && chown -R ${USER}:${USER} /etc/nginx \
+    && chown -R www-docker:www-docker /etc/nginx \
     && find /etc/nginx -type d -exec chmod 770 {} \; \
     && find /etc/nginx -type f -exec chmod 660 {} \;
 USER www-docker