L2SS-982 updated README for adding new devices

tangostationcontrol/tangostationcontrol/devices/README.md

@@ -18,3 +18,4 @@ If a new device is added, it will (likely) need to be referenced in several plac
 - Add to `tangostationcontrol/docs/source/devices/` to mention the device in the end-user documentation.
 - Adjust `tangostationcontrol/docs/source/index.rst` to include the newly created file in `docs/source/devices/`.
 - Adjust `docker-compose/tango-prometheus-exporter/lofar2-policy.json` to include this device in the prometheus exporter
+- Adjust `tangostationcontrol/tangostationcontrol/devices/docker_device.py` to have the device container available as an R and RW attribute. 
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