heroku application errorについて

ブラウザからURLを開こうとすると、application erroが出てしまします。
ターミナルでheroku run rails cを実行すると、

Running rails c on ⬢ myapp2525... up, run.9017 (Free)
Traceback (most recent call last):
	91: from /app/bin/rails:9:in `<main>'
	90: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
	89: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
	88: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-oad_path_cache/core_ext/kernel_require.rb:23:in `require'
	20: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/base.rb:27:in `<main>'
	19: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/base.rb:327:in `<module:ActiveRecord>'
	18: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:51:in `run_load_hooks'
	17: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:51:in `each'
	16: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:52:in `block in run_load_hooks'
	15: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:66:in `execute_hook'
	14: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:61:in `with_execution_control'
	13: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:71:in `block in execute_hook'
	12: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.5/lib/active_support/lazy_load_hooks.rb:71:in `class_eval'
	11: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/railtie.rb:201:in `block (2 levels) in <class:Railtie>'
	10: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/connection_handling.rb:51:in `establish_connection'
	 9: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:1052:in `establish_connection'
	 8: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/connection_adapters/connection_specification.rb:169:in `spec'
	 7: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.2/lib/zeitwerk/kernel.rb:34:in `require'
	 6: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
	 5: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
	 4: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	 3: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
	 2: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
	 1: from /app/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.3.5/lib/active_record/connection_adapters/sqlite3_adapter.rb:13:in `<main>'
/app/vendor/bundle/ruby/2.6.0/gems/bundler-2.1.4/lib/bundler/rubygems_integration.rb:346:in `block (2 levels) in replace_gem': Error loading the 'sqlite3' Active Record adapter. Missing a gem it depends on? sqlite3 is not part of the bundle. Add it to your Gemfile. (LoadError)

gemgileのLoadErrorが出てしまいます。

gemfileの中身は

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.6.5'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 6.0.3', '>= 6.0.3.3'
# Use sqlite3 as the database for Active Record
#gem 'sqlite3', '~> 1.4'
# Use Puma as the app server
gem 'puma', '~> 4.1'
# Use SCSS for stylesheets
gem 'sass-rails', '>= 6'
# Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
gem 'webpacker', '~> 4.0'
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.7'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use Active Model has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Active Storage variant
# gem 'image_processing', '~> 1.2'

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', '>= 1.4.2', require: false

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  gem 'sqlite3'
end

group :development do
  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '~> 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

group :test do
  # Adds support for Capybara system testing and selenium driver
  gem 'capybara', '>= 2.15'
  gem 'selenium-webdriver'
  # Easy installation and use of web drivers to run system tests with browsers
  gem 'webdrivers'
end

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

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

gem "haml-rails", ">= 1.0", '<= 2.0.1'

このようになっています。

# SQLite. Versions 3.8.0 and up are supported.
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
#
default: &default
  adapter: sqlite3
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: db/test.sqlite3

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

database.ymlはこのようにしています。

仮説
sql3が誤作動を起こしているように思われます。
どなたかご教授お願い致します。