title: How to send user notifications using django-channels 2.0?
body: <p>I am working on a chat app that has Rooms. Each room has two users. A user can be in multiple rooms i.e, a user has multiple rooms. And now he is chatting in one room. But he receives a message in another room. I would like to notify about the message from other room to the user. How should I implement this?﻿</p>
  
  <p>Currently a websocket connection is established as: <code>ws://localhost:8000/chat/int&lt;room_id&gt;/</code></p>
  
  <p>And the group_name is named as <code>"room"+room_id</code>. and So far I have:</p>
  
  <pre><code>async def connect(self):
      room_id = self.scope['url_route']['kwargs']['room_id']
      await self.channel_layer.group_add(
              "room"+room_id,
              self.channel_name
          )
      await self.accept()
  
  async def receive(self, text_data):
      await self.channel_layer.group_send(
          self.room_name,
          {
              'type': 'chat_message',
              'message': json.loads(text_data)
          }
      )
  async def chat_message(self, event):
      await self.send(text_data=json.dumps({
          'message': event['message']
      }))
  </code></pre>
  
  <p>Django 2.x
  django-channels 2.x
  python 3.6</p>