title: rails 5 - Create channel per conversation by ActionCable
body: <p>I'm a new Rails developer and getting start to use ActionCable in Rails 5 to create a chat app.</p>
  
  <p>The problem is that there are many chat examples in the Internet using ActionCable, but all of them are quite simple. They create a channel and all users connect to this channel can sent or read the messages from others.</p>
  
  <p>For example, they create a Chat channel like this:</p>
  
  <pre><code>class ChatChannel &lt; ApplicationCable::Channel
    def subscribed
      stream_from 'messages'
    end
  
    def speak(data)
      ActionCable.server.broadcast('messages',
        message: render_message(data['message']))
    end
  
    private
  
    def render_message(message)
      ApplicationController.render(partial: 'messages/message',
                                   locals: { message: message })
    end
  end
  </code></pre>
  
  <p>And in the client side, they connect to that channel</p>
  
  <pre><code>App.chat = App.cable.subscriptions.create "ChatChannel",
    received: (data) -&gt;
      $('#messages').append(data.message)
  
    speak: (msg) -&gt;
      @perform 'speak', message: msg
  </code></pre>
  
  <p>How can I create a channel per conversation between 2 users ?</p>