update Demo

Author: mgckind

demo1/Dockerfile

@@ -1,2 +1,8 @@
+# nginx:alpine is a very lightweight version of the web server nginx
 FROM nginx:alpine
+
+# We copy the index.html to the default path for nginx
 ADD index.html /usr/share/nginx/html
+
+# No need to add ENTRYPOINT or CMD since is already included in the nginx image
+# https://github.com/nginxinc/docker-nginx/blob/f603bb3632ea6df0bc9da2179c18eb322c286298/mainline/alpine/Dockerfile