* A new "hello world" example is added

* The directory `docker/system` has been moved to `docker/main`

docker/main/README.md

@@ -0,0 +1,63 @@
+# Clixon example test container
+
+This directory show how to build a "monolithic" clixon docker
+container exporting port 80 and contains the example application with
+both restconf, netconf, cli and backend. It also includes packages to be able to run the [Clixon tests](../../test).
+
+The directory contains the following files:
+	 cleanup.sh     kill containers
+	 Dockerfile     Docker build instructions
+	 Makefile.in    "make docker" builds the container
+	 README.md	This file
+	 start.sh       Start containers
+	 startsystem.sh Internal start script copied to inside the container (dont run from shell)
+
+How to build and start the container (called clixon-system):
+```
+  $ make docker
+  $ ./start.sh 
+```
+
+The start.sh has a number of environment variables to alter the default behaviour:
+* PORT - Nginx exposes port 80 per default. Set `PORT=8080` for example to access restconf using 8080.
+* DBG - Set debug. The clixon_backend will be shown on docker logs.
+* CONFIG - Set XML configuration file other than the default example.
+* STORE - Set running datastore content to other than default.
+
+Example:
+```
+  $ DBG=1 PORT=8080 ./start.sh
+```
+
+Once running you can access it in different ways as follows:
+As CLI:
+```
+  $ sudo docker exec -it clixon-system clixon_cli
+```
+As netconf via stdin/stdout:
+```
+  $ sudo docker exec -it clixon-system clixon_netconf
+```
+As restconf using curl on exposed port 80:
+```
+  $ curl -G http://localhost/restconf
+```
+Or run tests:
+```
+  $ sudo docker exec -it clixon-system bash -c 'cd /usr/local/bin/test && ./all.sh'
+```
+
+To check status and then kill it:
+```
+  $ sudo docker ps --all
+  $ ./cleanup.sh 
+```
+
+You trigger the test scripts inside the container using `make test`.
+
+## Changing code
+
+If you want to edit clixon code so it runs in the container?
+You either
+(1) "persistent": make your changes in the actual clixon code and commit; make clean to remove the local clone;  make test again
+(2) "volatile" edit the local clone; make test.