herokuとlocalhostが使えない

Question

前提・実現したいこと

herokuのApplication errorを解決してherokuにデプロイしたい。
現在railsチュートリアルの７章をしており後半にある本番環境へのデプロイという項目でつまづいています。

手順通りに進めていてSSLを使うためにproduciton.rbで

config.force_ssl = true

と記述し、config/puma.rbでは

workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['RAILS_MAX_THREADS'] || 5)
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup
port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'

on_worker_boot do
  # Worker specific setup for Rails 4.1+
  # See: https://devcenter.heroku.com/articles/
  # deploying-rails-applications-with-the-puma-web-server#on-worker-boot
  ActiveRecord::Base.establish_connection
end

と記述し、Gemfileと同じディレクトリにProcfileを作り

web: bundle exec puma -C config/puma.rb

と記述しました。

そして

$ rails test
$ git add -A
$ git commit -m "Use SSL and the Puma webserver in production"
$ git push
$ git push heroku
$ heroku run rails db:migrate
$ heroku open

としたところ下記のエラーが！

発生している問題・エラーメッセージ

Application error
An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details. You can do this from the Heroku CLI with the command
heroku logs --tail

該当のソースコード

heroku logs --tailをすると以下のようなログが出てきた

2018-11-22T11:34:40.086650+00:00 app[web.1]: /app/vendor/bundle/ruby/2.5.0/bin/puma:23:in `<top (required)>'
2018-11-22T11:34:40.226396+00:00 heroku[web.1]: State changed from starting to up
2018-11-22T11:34:40.325090+00:00 heroku[web.1]: Process exited with status 1
2018-11-22T11:34:40.344523+00:00 heroku[web.1]: State changed from up to crashed
2018-11-22T11:34:40.346434+00:00 heroku[web.1]: State changed from crashed to starting
2018-11-22T11:34:45.832518+00:00 heroku[web.1]: Starting process with command `bundle exec puma -C config/puma.rb`
2018-11-22T11:34:48.927632+00:00 app[web.1]: [4] Puma starting in cluster mode...
2018-11-22T11:34:48.927676+00:00 app[web.1]: [4] * Version 3.12.0 (ruby 2.5.1-p57), codename: Llamas in Pajamas
2018-11-22T11:34:48.927679+00:00 app[web.1]: [4] * Min threads: 5, max threads: 5
2018-11-22T11:34:48.927685+00:00 app[web.1]: [4] * Environment: production
2018-11-22T11:34:48.927687+00:00 app[web.1]: [4] * Process workers: 2
2018-11-22T11:34:48.927689+00:00 app[web.1]: [4] * Preloading application
2018-11-22T11:34:52.913838+00:00 app[web.1]: [4] * Listening on tcp://0.0.0.0:51726
2018-11-22T11:34:52.914067+00:00 app[web.1]: [4] * Listening on tcp://0.0.0.0:51726
2018-11-22T11:34:52.914320+00:00 app[web.1]: bundler: failed to load command: puma (/app/vendor/bundle/ruby/2.5.0/bin/puma)
2018-11-22T11:34:52.914349+00:00 app[web.1]: Errno::EADDRINUSE: Address already in use - bind(2) for "0.0.0.0" port 51726

2018-11-22T11:34:53.124010+00:00 heroku[web.1]: State changed from starting to crashed
2018-11-22T11:34:53.103282+00:00 heroku[web.1]: Process exited with status 1
2018-11-22T11:34:58.961604+00:00 app[api]: Starting process with command `rails db:migrate` by user [e-mail]
2018-11-22T11:35:03.224704+00:00 heroku[run.4141]: Awaiting client
2018-11-22T11:35:03.258519+00:00 heroku[run.4141]: Starting process with command `rails db:migrate`
2018-11-22T11:35:03.525543+00:00 heroku[run.4141]: State changed from starting to up
2018-11-22T11:35:09.819836+00:00 heroku[run.4141]: Process exited with status 0
2018-11-22T11:35:09.837067+00:00 heroku[run.4141]: State changed from up to complete
2018-11-22T11:35:23.106081+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=radiant-ridge-30387.herokuapp.com request_id=1c0490e3-eb04-45c1-98ed-abafb1358ebf fwd="60.100.247.250" dyno= connect= service= status=503 bytes= protocol=https
2018-11-22T11:35:23.775653+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=radiant-ridge-30387.herokuapp.com request_id=d9105058-eddd-427b-b8d9-5a5b5cd66932 fwd="60.100.247.250" dyno= connect= service= status=503 bytes= protocol=https
2018-11-22T11:36:33.769854+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=radiant-ridge-30387.herokuapp.com request_id=ebbe82d6-9987-4ee1-b825-33d5952964d9 fwd="60.100.247.250" dyno= connect= service= status=503 bytes= protocol=https
2018-11-22T11:36:34.179219+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=radiant-ridge-30387.herokuapp.com request_id=75347f38-9984-4e4a-913a-2b0fbb247bdf fwd="60.100.247.250" dyno= connect= service= status=503 bytes= protocol=https

試したこと

ググってGemfileの下を

group :production do
  gem 'pg', '< 1.0.0'
end

にするといいとあったがそれをしても変わらない。

またrails sをしたところこれもエラーが出て

 Address already in use - bind(2) for "0.0.0.0" port 3000 (Errno::EADDRINUSE)

となってしまった。

どうか手助けお願いします。