title: socket.io emit message from one namespace to another
body: <p>I'm trying to emit a message from one namespace to another (on connection).
  Bellow is some sample code with how I was trying to approach it.</p>
  
  <p><strong>[Server]</strong></p>
  
  <pre><code>// Namespaces
  var users_ns = io.of('/users');
  var machines_ns = io.of('/machines');
  
  // Attempt to receive the event on the socket
  users_ns.on('connection', function(socket){
      socket.on('test', function(socket){
          console.log('socket test');
      });
  });
  
  // Attempt to receive the event on the namespace
  users_ns.on('test', function(socket){
      console.log('namespace test');
  });
  
  // Emit an event to the 'users' namespace
  machines_ns.on('connection', function(socket){
      users_ns.emit('test');
  });
  </code></pre>
  
  <p><strong>[Client1]</strong></p>
  
  <pre><code>var socket = io('http://localhost/users');
  </code></pre>
  
  <p><strong>[Client2]</strong></p>
  
  <pre><code>var socket = io('http://localhost/machines');
  </code></pre>
  
  <p>Any idea why this doesn't work?</p>