lib/websockets.js
function (users, args) {
    for (var i = 0; i < users.length; i++) {
      if (!this.sockets[users[i]]) continue;
      this.sockets[users[i]].emit(args);
    }
  }
function (users, args) {
    for (var i = 0; i < users.length; i++) {
      if (!this.sockets[users[i]]) continue;
      this.sockets[users[i]].emit(args);
    }
  }
send a message to a number of users send([uid, uid, ...], arguments)