title: authenticating users / socket io
body: <p>I'm new to this, i'm building a game where users need to log in and can interact with each other, or a subset of other currently logged in users. </p>
  
  <p>My initial thought is that after they login add them/their websocket client id to an array of currently logged in users and have that be what I manipulate to know who is logged in or not. </p>
  
  <p>Is this a normal way to go about doing this sort of thing? </p>
  
  <p>Thanks!</p>