add an example of docker ps, and also of link aliases

a question from irc prompted me to add a little more info :)

@metalivedev

```
<jjjjjosh> does anyone know why, when you do `docker ps` the column is called "names" and not "name"?
<jjjjjosh> i'm mostly curious
* kennethreitz has quit (Quit: Textual IRC Client: www.textualapp.com)
* ngpestelos (~textual@122.53.113.50) has joined #docker
<jjjjjosh> i tried doing `sudo docker run -d -name foo -name bar ubuntu /bin/sh -c "while true; do echo Hello world; sleep 1; done"`
* mrunalp has quit (Ping timeout: 246 seconds)
<jjjjjosh> and it just takes the last name (so, "bar")
* siong1987 has quit (Quit: My MacBook has gone to sleep. ZZZzzz…)
* ccs (~ccs@c-76-126-102-42.hsd1.ca.comcast.net) has joined #docker
<jamesottaway> if you spawn another container and link it to the first, you'll see another name on the first container
<jamesottaway> so spawn foo, then spawn bar and link to foo
<jamesottaway> the names for foo will be 'foo' and 'bar/foo'
<jjjjjosh> awesome thanks!
```