Update README.md

update the doc

Author: perigee

README.md

@@ -11,14 +11,48 @@ The premier high-level javascript graphing library
 
 ### Run container
 
+Under your `plotly.js` folder, run
+
 ```bash
 $ docker run -d --name your_container_name \
-                      -v $PWD/plotlyjs:/var/www/streambed/image_server/plotlyjs \
+                      -v $PWD:/var/www/streambed/image_server/plotlyjs \
 		      -p 9010:9010 -p 2022:22 plotly/imageserver:[version]
 ```
 
 ### Run the test
 
 ```bash
 $ docker exec -i your_container_name /bin/bash -c "cd /var/www/streambed/image_server/plotlyjs && npm run test-image"
-``` 
+``` 
+
+### SSH into docker
+
+```bash
+$ ssh -p 2022 root@localhost # with password `root`
+```
+
+if you got error
+
+```
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
+Someone could be eavesdropping on you right now (man-in-the-middle attack)!
+It is also possible that a host key has just been changed.
+The fingerprint for the ECDSA key sent by the remote host is
+dd:1e:e0:95:8d:ef:06:b8:0f:2f.
+Please contact your system administrator.
+Add correct host key in /home/jh/.ssh/known_hosts to get rid of this message.
+Offending ECDSA key in /home/jh/.ssh/known_hosts:104
+  remove with: ssh-keygen -f "/home/jh/.ssh/known_hosts" -R [localhost]:2022
+ECDSA host key for [localhost]:2022 has changed and you have requested strict checking.
+Host key verification failed.
+```
+simply run
+
+```bash
+$ ssh-keygen -f "/home/jh/.ssh/known_hosts" -R [localhost]:2022
+```
+
+to remove host information.