Added Heroku deployment container update steps

Author: NaohiroTamura

heroku/Dockerfile

@@ -23,5 +23,5 @@ RUN rm /bin/sh && ln -s /bin/bash /bin/sh && \
     mkdir /logs && chmod 0777 /logs && \
     ln -s /dev/stderr /logs/httpd.log
 
-CMD if [ -e etc/server ]; then rm -rf etc/server ; fi && \
-    FAASSHELL_SVC_PORT=$PORT swipl -q -l src/faasshell_svc.pl -g main -t halt
+# The web process must listen for HTTP traffic on $PORT, which is set by Heroku.
+CMD FAASSHELL_SVC_PORT=$PORT swipl -q -l src/faasshell_svc.pl -g main -t halt

heroku/README.md

@@ -1,5 +1,7 @@
 # Heroku deployment steps
 
+## Initial Install
+
 ```sh
 ubuntu@xenial:~/faasshell/heroku[master]$ heroku login
 
@@ -16,6 +18,22 @@ ubuntu@xenial:~/faasshell/heroku[master]$ heroku container:push web --app protec
 ubuntu@xenial:~/faasshell/heroku[master]$ heroku container:release web --app protected-depths-49487
 
 ubuntu@xenial:~/faasshell/heroku[master]$ curl https://protected-depths-49487.herokuapp.com/ -u $DEMO
+{"version":"$Id rev.2018-07-08.2e2c6c4 $"}
 
 ubuntu@xenial:~/faasshell/heroku[master]$ heroku logs --app protected-depths-49487 -t
 ```
+
+## Update Install
+
+```sh
+ubuntu@xenial:~/faasshell/heroku[master]$ heroku login
+
+ubuntu@xenial:~/faasshell/heroku[master]$ heroku container:login
+
+ubuntu@xenial:~/faasshell/heroku[master]$ heroku container:push web --app protected-depths-49487
+
+ubuntu@xenial:~/faasshell/heroku[master]$ heroku container:release web --app protected-depths-49487
+
+ubuntu@xenial:~/faasshell/heroku[master]$ curl https://protected-depths-49487.herokuapp.com/ -u $DEMO
+{"version":"$Id rev.2018-11-16.1a84b0a $"}
+```