ARTEMIS-2245 adding Docker images User guide

docs/user-manual/en/SUMMARY.md

@@ -72,4 +72,5 @@
 * [Maven Plugin](maven-plugin.md)
 * [Unit Testing](unit-testing.md)
 * [Troubleshooting and Performance Tuning](perf-tuning.md)
+* [Docker support](docker.md)
 * [Configuration Reference](configuration-index.md)

docs/user-manual/en/docker.md

@@ -0,0 +1,26 @@
+# Artemis on Docker
+
+Artemis provide support to build CentOS and Ubuntu images of the broker, allowing to reuse 
+an existing broker instance *ie from a previous image run* or just creating a fresh new one.
+
+## Building a CentOS image
+From within the folder with both `Dockerfile-centos` file and `assets` folder:
+```
+$ docker build -f Dockerfile-centos -t artemis-centos .
+```
+> **Note:**
+>`-t artemis-centos` is just a tag name for the purpose of this guide
+## Running a CentOS image
+The image just created in the previous step allows both stateless or stateful runs.
+The stateless run is achieved by:
+```
+$ docker run --rm -it -p 61616:61616 -p 8161:8161 artemis-centos 
+```
+While a stateful run with:
+```
+docker run -it -p 61616:61616 -p 8161:8161 -v <broker folder on host>:/var/lib/artemis-instance artemis-centos 
+```
+where `<broker folder on host>` is a folder where the broker instance is supposed to 
+be saved and reused on each run.
+
+