Problems with implementing a realtime update with Rails5 and Actioncable - ruby

Question

I'm trying to implement a simple rails fullstack todo app with action cable.
Unfortunately the docs on action cable is still confusing to me.
I tried to refer to DHH's example and https://blog.heroku.com/real_time_rails_implementing_websockets_in_rails_5_with_action_cable and adjusting to my app https://github.com/tenzan/rails-fullstack-todo
It's not showing realtime updates at http://localhost:3000/tasks when I used one browser for task creation and another one to see if it changes automatically.
My environment:
Mac OS X Sierra
Rails 5.0.0.1
Ruby 2.4.0
Redis enabled in Gemfile and running at port 6379
RethinkDB
I implemented:
app/assets/javascripts/channels/index.coffee
//= require cable
//= require_self
//= require_tree .
this.App = {};
App.cable = ActionCable.createConsumer();
app/assets/javascripts/channels/tasks.js
App.tasks = App.cable.subscriptions.create('TasksChannel', {
received: function(data) {
$("#tasks").removeClass('hidden')
return $('#tasks').append(this.renderTask(data));
}
});
app/channels/tasks_channel.rb
class TasksChannel < ApplicationCable::Channel
def subscribed
stream_from "tasks"
end
def unsubscribed
# Any cleanup needed when channel is unsubscribed
end
app/controllers/tasks_controller.rb
def create
#task = Task.new(task_params)
respond_to do |format|
if #task.save
ActionCable.server.broadcast 'tasks', task: #task.title
format.html { redirect_to tasks_url, notice: 'Task was successfully created.' }
format.json { render :show, status: :created, location: #task }
else
format.html { render :new }
format.json { render json: #task.errors, status: :unprocessable_entity }
end
end
end
app/views/layouts/application.html.erb: Added <%= action_cable_meta_tag %>
config/cable.yml
local: &local
url: redis://localhost:6379
development: *local
test: *local
config/environments/development.rb
Rails.application.configure do
config.action_cable.url = "ws://localhost:3000/cable"
config/routes.rb
Rails.application.routes.draw do
mount ActionCable.server => '/cable'
app/views/tasks/index.html.erb
I suspect something wrong with
app/assets/javascripts/channels/tasks.coffee
app/views/tasks/index.html.erb
But I really don't have an idea how to fix/adjust them.