How to completely remove webpack and all its dependencies from Rails App - ruby-on-rails

Question

I created my rails with this template that included webpack, I still write my javascript code in app/assets/javascript. I am trying to deploy my app to heroku and it keeps failing, I get this error
"remote:
/tmp/build_6f0656280cbbda40c5832ccb79fc1783/vendor/bundle/ruby/2.3.0/gems/bundler-1.15.2/lib/bundler/rubygems_integration.rb:432:in
`block in replace_bin_path': can't find executable webpack for gem
webpacker (Gem::Exception)"
I have tried lots of solutions but still cant get my app deployed to Heroku. I want to know how to completely delete webpack and all its depencies from my app since it was not even useful to my app
source 'https://rubygems.org'
ruby '2.3.5'
gem 'figaro'
gem 'jbuilder', '~> 2.0'
gem 'puma'
gem 'rails', '5.1.4'
gem 'redis'
gem 'cloudinary'
gem 'carrierwave', '~> 1.2'
gem 'rails_admin', '~> 1.2'
group :production do
gem 'pg', '~> 0.20'
end
gem 'autoprefixer-rails'
gem 'bootstrap-sass'
gem 'jquery-rails'
gem 'font-awesome-sass'
gem 'sass-rails'
gem 'simple_form'
gem 'turbolinks', '~> 5.0.0'
gem 'coffee-rails'
gem 'uglifier'
gem 'webpacker'
gem 'devise'
gem 'ransack'
gem 'trix'
gem "letter_opener", group: :development
group :development do
gem 'web-console', '>= 3.3.0'
gem 'sqlite3'
end
group :development, :test do
# gem 'binding_of_caller'
# gem 'better_errors'
gem 'pry-byebug'
gem 'pry-rails'
gem 'listen', '~> 3.0.5'
gem 'spring'
gem 'spring-watcher-listen', '~> 2.0.0'
end

Answer 1

remove bin/webpackor run bundle exec rake rails:update:bin
remove config/webpacker.yml
remove config/webpack
remove app/javascripts
remove config.webpacker.check_yarn_integrity = false from config/{development, test, production}.rb
verify that you don't have webpacker in your gemfile and run bundle install or bundle clean
imho, don't create your rails app with generators (unless it's your own)