Rails 本番環境でのundefind method chartkick

#解決したい事

chartkickを使ったRailsアプリをherokuにデプロイし、確認した所不具合が発生しました。
logを確認すると

#エラーメッセージ

FATAL -- : [5973794e-1475-45ea-bbfa-922e8b05b144]
2020-11-14T06:28:59.463980+00:00 app[web.1]: [5973794e-1475-45ea-bbfa-922e8b05b144] ActionView::Template::Error (undefined method `line_chart' for #<#<Class:0x000055df9ff8be00>:0x000055df9fb31e68>):

このようなエラーが出ています。

ローカルでは普通に動いてたchartkickが読み込まれていないという事でしょうか？
heroku run rails dbconsoleでデーターベースを確認しましたが特におかしいところはありませんでした。

わかる方いましたら是非知恵を貸して頂きたいです。
よろしくお願いします。

#該当のソースコード

<%= line_chart @user.records.limit(30).pluck(:date, :level) %>

aoolication.js

require("@rails/ujs").start();
require("turbolinks").start();
require("@rails/activestorage").start();
require("channels");
require("jquery");
require("chartkick");
require("chart.js");
require("check.js");
require("modal.js");

Gemfile

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

ruby '2.6.3'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 6.0.3'
# 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'
gem 'devise'
gem 'bootstrap', '~> 4.1.1'
gem 'jquery-rails'
gem 'font-awesome-rails'
gem "refile", require: "refile/rails", github: 'manfe/refile'
gem "refile-mini_magick"
gem 'mini_racer'
gem 'faker'
gem 'devise-i18n'
gem 'devise-i18n-views'
# 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
  gem 'sqlite3', '1.4.1'
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
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'
  gem 'better_errors'
  gem 'binding_of_caller'
  gem "rails-erd"
  gem 'pry-rails'
  gem "chartkick"
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', '1.1.4'
end

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

#試した事

production.rb