userJoining (the user starting from html5 client) is also joined via user_joined_event

client/bbb-html5-client/lib/redis_publisher.coffee

client/bbb-html5-client/lib/redis_websocket_bridge.coffee

client/bbb-html5-client/public/js/collections/users.coffee

client/bbb-html5-client/public/js/models/connection.coffee

client/bbb-html5-client/public/js/views/session_chat.coffee