Unable to subscribe to new user channel when logged in as another uaer

[tensiuyan]

No description provided.

[carmenlau]

After merging commit #110, the usage example should be.

When user login

• To subscribe user channel we should call as follow:

  skygearChat.pubsub.subscribeUserChannel();
  

• Calling subscribe message will also help auto subscribe user channel

  skygearChat.subscribe(function(){...});
  

  or

  skygearChat.pubsub.subscribeMessage(function(){...});
  

When user logout

• Should unsubscribe user channel

  skygearChat.pubsub.unsubscribeUserChannel();
  

[carmenlau]

@tensiuyan Released v1.6.3 chat JS SDK