demo: Updated docs and added socat forwarding container

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

projects/demo/README.md

@@ -27,6 +27,19 @@ cp Contents/MacOS/vpnkit /Applications/Docker.app/Contents/Resources/bin/
 Restart Docker for Mac.
 
 
+# Local setup
+
+We use a `socat` container to forward ports from the VM to localhost (via Docker for Mac), to make it easier to access some VMs. To build
+```
+(cd dockerfiles; docker build -t socat -f Dockerfile.socat .)
+```
+And then run:
+```
+docker run --rm -t -d -p 8080:8080 socat tcp-listen:8080,reuseaddr,fork tcp:192.168.65.100:80
+```
+This forwards local port `8080` to `192.168.65.100:80`, so if you start, say the `intro` image, run `moby run -ip 196.168.65.100 intro`
+
+
 # GCP Setup
 
 You probably want to change the project/zone

projects/demo/dockerfiles/Dockerfile.socat

@@ -0,0 +1,8 @@
+# A dockerfile to build a socat container
+#
+# It sets the environment to talk to the local cluster
+FROM alpine:edge
+
+RUN apk add --no-cache socat
+
+ENTRYPOINT [ "/usr/bin/socat" ]