Deployed Rails 4.2.4 on heroku but can't run app - ruby-on-rails

Question

I created a Rails 4.2.4 app and deployed it to Heroku without adding any code. It runs fine on localhost but not on Heroku. Here are the Heroku logs:
at=info method=GET path="/" host=bagala.herokuapp.com request_id=b838aff9-e39b-4e32-8407-8d3e10da8117 fwd="178.91.253.104" dyno=web.1 connect=0ms service=3ms status=404 bytes=228
Note that sometimes I get status 404. It is quite strange. Have no Idea what is happening?
Here is my gemfile:
source 'https://rubygems.org'
ruby '2.2.0'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.4'
# Use postgresql as the database for Active Record
gem 'pg'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use Unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
group :development, :test do
# Call 'byebug' anywhere in the code to stop execution and get a debugger console
gem 'byebug'
end
group :development do
# Access an IRB console on exception pages or by using <%= console %> in views
gem 'web-console', '~> 2.0'
# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring'
end

Answer 1

Of course you will receive error 404 because this is a fresh Rails app, you didn't add any routes to it. On development environment, Rails will show you a welcome page, but on production environment, it will be a 404 page because the application actually doesn't have any page to show to user.