document the Makefile commands; link to solid forum

Author: angelo-v

README.md

@@ -4,12 +4,40 @@ Containerized version of node-solid-server
 
 ## How to use
 
-This is still work in progress and not meant to be used yet.
+This is still work in progress and not meant to be used in production yet.
+
+If you want to experiment with the image and/or contribute to its development,
+please read the rest of this ReadMe.
 
 ## Run tests
 
-```
+```bash
 make test
 ```
 
-The first run might take a while, since the image has to be build. Follow up test runs will be faster.
+The first run might take a while, since the image has to be build. Follow up test runs will be faster.
+
+## Start & stop locally
+
+Build and run a local container named solid-server via
+
+```bash
+make start
+```
+
+and stop it via 
+
+```bash
+make stop
+```
+
+## Inspect & debug
+
+To start a shell in a running container (started with `make start`) run `make attach`.
+
+To just run a shell in the built image (without starting solid) run `make inspect`.
+
+## Feedback & Discussion
+
+There is a [topic in the Solid Forum](https://forum.solidproject.org/t/official-solid-docker-image/748/5),
+you are welcome to join in.