Update linking documentation

As of 1.3 `docker ps` no longer shows links between containers.                                                                                       
This updates the documentation to reflect that change.                                                                                                
The command to inspect the links I chose is:                                                                                                                  
                                                                                                                                                      
    $ sudo docker inspect -f "{{ .HostConfig.Links }}" web

I build the documentation and LGTM. But if there is anything you want me to adjust
feel free to tell me.