Merge Dockerfile and example files for backend support example (#7)

* Add template dockerfile for testing

* Switch to holo-docker image

* Add default entrypoint.sh

* Updated dockerfile to reflect CI/CD on database

* Add template makefile, main.c

* Adjusted entrypoint.sh to actually build binary

* Made entrypoint.sh executable

* Big README update and comments in Dockerfile

backend/entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+set -e
+
+echo "Container's IP address: `awk 'END{print $1}' /etc/hosts`"
+
+cd /backend
+
+make