updated to UBI and get backend host from env

todo-frontend/Dockerfile

@@ -0,0 +1,26 @@
+FROM registry.access.redhat.com/ubi8:8.0
+
+LABEL version="1.0"
+LABEL description="To Do List application front-end"
+LABEL creationDate="2017-12-25"
+LABEL updatedDate="2019-08-01"
+
+ENV BACKEND_HOST=localhost:8081
+
+RUN yum install -y --disableplugin=subscription-manager --nodocs nginx nginx-mod-http-perl
+RUN yum clean all
+
+ADD nginx.conf /etc/nginx/
+
+RUN touch /run/nginx.pid
+RUN chgrp -R nginx /var/log/nginx /run/nginx.pid
+RUN chmod -R g+rwx /var/log/nginx /run/nginx.pid
+  
+ADD src/ /usr/share/nginx/html
+
+EXPOSE 8080
+
+USER nginx
+
+CMD nginx -g "daemon off;"
+