Use server/namespace to broadcast

[tomasvidhall]

This line in the README suggests that you should be able to use the server to send messages to all clients in a room. When I do that I end up with the stacktrace below error.
io.to('room42').emit('hello', "to all clients in 'room42' room");

Not sure if I have understood how to use the server/namespace correctly, but I found this bug in my app when I wanted to update to socketio v3. In my app I want the server to broadcast a message to a specific room and that triggers the following stacktrace.

TypeError: opts.except is not iterable
  at RedisAdapter.broadcast (/usr/src/node_modules/socket.io-redis/dist/index.js:255:34)
  at Namespace.emit (/usr/src/node_modules/socket.io/dist/namespace.js:175:22)
  at Server.<computed> [as emit] (/usr/src/node_modules/socket.io/dist/index.js:442:33)
  at /usr/src/services/websocket-handler-service/src/events/rooms.js:13:25
  at /usr/src/packages/message-broker/index.js:28:5
  at Array.forEach (<anonymous>)
  at Redis.<anonymous> (/usr/src/packages/message-broker/index.js:27:22)
  at Redis.emit (events.js:315:20)
  at DataHandler.handleSubscriberReply (/usr/src/node_modules/ioredis/built/DataHandler.js:80:32)
  at DataHandler.returnReply (/usr/src/node_modules/ioredis/built/DataHandler.js:47:18)

Please either merge this PR or explain to me how I'm supposed to broadcast a message to a specific room. (tried to do it with client.broadcast.to(roomId), but that doesn't actually send it to everyone in the room. My guess is that it's because the client doesn't actually know what sockets are in the specified room.

[cstrnt]

Having the same problem; The same syntax works without the adapter

[darrachequesne]

@tomasvidhall arf, thanks a lot 👍