update README for tutorial

[blue0513]

Problem

Run dsps server by docker run

$ docker run --rm -p 3000:3099/tcp saiya/dsps:latest
$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                              NAMES
cd0d7f0ad77f        saiya/dsps:latest   "./dsps"                 9 minutes ago       Up 9 minutes        3000/tcp, 0.0.0.0:3000->3099/tcp   adoring_zhukovsky

But curl failed

$ curl -X PUT "http://localhost:3099/channel/${CHANNEL}/subscription/polling/${SUBSCRIBER}"
curl: (7) Failed to connect to localhost port 3099: Connection refused

Solution

Fix -p option usage.

docker run --rm -p 3099:3000/tcp saiya/dsps:latest

After that, we can access webserver running on port 3000 by curl -X PUT "http://localhost:3099"

[saiya]

Oops. Thanks.