[RaislTutorial]Herokuにデプロイした際にApplicationErrorが発生する

Question

自分で調べた中でも同じような質問がいくつか見受けられたのですが、解決に至らなかったので質問させていただきます。

RailsTutorial1．5.2で起こった事象になります。

ローカル上では問題なく動くのですがHerokuへデプロイするとエラーが発生してしまいます。

###実行環境
・Ruby（2.4.4）
・Rails（5.1.6）
・Heroku（7.14.1）

以下がGemfileです

source 'https://rubygems.org'

gem 'rails',        '5.1.6'
gem 'puma',         '3.9.1'
gem 'sass-rails',   '5.0.6'
gem 'uglifier',     '3.2.0'
gem 'coffee-rails', '4.2.2'
gem 'jquery-rails', '4.3.1'
gem 'turbolinks',   '5.0.1'
gem 'jbuilder',     '2.7.0'

group :development, :test do
  gem 'sqlite3', '1.3.13'
  gem 'byebug',  '9.0.6', platform: :mri
end

group :development do
  gem 'web-console',           '3.5.1'
  gem 'listen',                '3.1.5'
  gem 'spring',                '2.0.2'
  gem 'spring-watcher-listen', '2.0.1'
end

group :production do
  gem 'pg', '0.20.0'
end

# Windows環境ではtzinfo-dataというgemを含める必要があります
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

###エラー
以下がエラーが発生した際のHerokuのログとRailsConsoleの出力になります。

2018-09-06T07:08:09.366804+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
2018-09-06T07:08:09.366824+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/command/base.rb:63:in `perform'2018-09-06T07:08:09.366843+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/command.rb:44:in `invoke'
2018-09-06T07:08:09.366866+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/commands.rb:16:in `<top (required)>'
2018-09-06T07:08:09.366890+00:00 app[web.1]: from bin/rails:9:in `require'
2018-09-06T07:08:09.366909+00:00 app[web.1]: from bin/rails:9:in `<main>'
2018-09-06T07:08:09.374706+00:00 app[web.1]: => Booting Puma
2018-09-06T07:08:09.374709+00:00 app[web.1]: => Rails 5.1.6 application starting in production
2018-09-06T07:08:09.374711+00:00 app[web.1]: => Run `rails server -h` for more startup options
2018-09-06T07:08:09.374713+00:00 app[web.1]: Exiting
2018-09-06T07:08:11.863126+00:00 heroku[web.1]: Starting process with command `bin/rails server -p 52611 -e production`
2018-09-06T07:08:15.257052+00:00 app[web.1]: /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/connection_specification.rb:188:in `rescue in spec': Specified 'sqlite3' for database adapter, but the gem is not loaded. Add `gem 'sqlite3'` to
your Gemfile (and ensure its version is at the minimum required by ActiveRecord). (Gem::LoadError)
2018-09-06T07:08:15.257075+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/connection_specification.rb:185:in `spec'
2018-09-06T07:08:15.257084+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:880:in `establish_connection'
2018-09-06T07:08:15.257089+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/connection_handling.rb:58:in `establish_connection'
2018-09-06T07:08:15.257091+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/railtie.rb:124:in `block (2 levels) in <class:Railtie>'
2018-09-06T07:08:15.257092+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:69:in `instance_eval'
2018-09-06T07:08:15.257093+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:69:in `block in execute_hook'
2018-09-06T07:08:15.257188+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/engine.rb:475:in `block in eager_load!'

2018-09-06T07:08:15.257365+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
2018-09-06T07:08:15.257343+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/thor-0.20.0/lib/thor/command.rb:27:in `run'
2018-09-06T07:08:15.257338+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/commands/server/server_command.rb:130:in `tap'
2018-09-06T07:08:15.257393+00:00 app[web.1]: from bin/rails:9:in `<main>'
2018-09-06T07:08:15.264009+00:00 app[web.1]: => Booting Puma
2018-09-06T07:08:15.264012+00:00 app[web.1]: => Rails 5.1.6 application starting in production
2018-09-06T07:08:15.257374+00:00 app[web.1]: from bin/rails:9:in `require'
2018-09-06T07:08:15.264014+00:00 app[web.1]: Exiting
2018-09-06T07:08:15.264013+00:00 app[web.1]: => Run `rails server -h` for more startup options
2018-09-06T07:08:15.327664+00:00 heroku[web.1]: State changed from starting to crashed
2018-09-06T07:08:15.314647+00:00 heroku[web.1]: Process exited with status 1
2018-09-06T07:08:16.063220+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=obscure-reaches-XXXXX.herokuapp.com request_id=cf6826c7-9a76-45bf-9f2b-557c70efd401 fwd="110.4.129.60" dyno= connect= service= status=503 bytes= protocol=https
2018-09-06T07:08:16.703105+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=obscure-reaches-XXXXX.herokuapp.com request_id=505a9c20-7b05-4848-92f3-b6bead41ae57 fwd="110.4.129.60" dyno= connect= service= status=503 bytes= protocol=https

/app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/connection_specification.rb:188:in `rescue in spec': Specified 'sqlite3' for database adapter, but the gem is not loaded. Add `gem 'sqlite3'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord). (Gem::LoadError)
        from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/connection_specification.rb:185:in `spec'
        from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:49:in `run_load_hooks'
        from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/base.rb:326:in `<module:ActiveRecord>'
        from /app/vendor/bundle/ruby/2.4.0/gems/activerecord-5.1.6/lib/active_record/base.rb:25:in `<top (required)>'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `block in require'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:258:in `load_dependency'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
        from /app/app/models/application_record.rb:1:in `<top (required)>'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `block in require'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:258:in `load_dependency'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
        from /app/vendor/bundle/ruby/2.4.0/gems/activesupport-5.1.6/lib/rails/engine.rb:475:in `each'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/engine.rb:475:in `block in eager_load!'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/engine.rb:473:in `each'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-
        from /app/vendor/ruby-2.4.4/lib/ruby/2.4.0/tsort.rb:226:in `tsort_each'
        from /app/vendor/ruby-2.4.4/lib/ruby/2.4.0/tsort.rb:205:in `tsort_each'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/initializable.rb:58:in `run_initializers'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/application.rb:353:in `initialize!'
        from /app/config/environment.rb:5:in `<top (required)>'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/application.rb:329:in `require'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/application.rb:329:in `require_environment!'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/command/actions.rb:16:in `require_application_and_environment!'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/commands/console/console_command.rb:96:in `perform'
        from /app/vendor/bundle/ruby/2.4.0/gems/thor-0.20.0/lib/thor/command.rb:27:in `run'
        from /app/vendor/bundle/ruby/2.4.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:in `invoke_command'
        from /app/vendor/bundle/ruby/2.4.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/command/base.rb:63:in `perform'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/command.rb:44:in `invoke'
        from /app/vendor/bundle/ruby/2.4.0/gems/railties-5.1.6/lib/rails/commands.rb:16:in `<top (required)>'
        from /app/bin/rails:9:in `require'
        from /app/bin/rails:9:in `<main>'

文字数制限のため一部省略しています。

試したこと　　

・gemfileに以下を追記する

gem 'sqlite3', groups: %w(test development), require: false
gem 'pg', groups: %w(production), require: false

特に変化なし

同じような質問が増えてしまうことに関しては申し訳ないのですがお力添えよろしくお願いします。

Answer 1

自己解決しました。

databese.ymlがsqliteのままだったためそこを修正したところ正常に動きました。

production:
  <<: *default
  adapter: postgresql
  database: db/production.pg