title: Adding ActiveAdmin to a RoR application using webpack
body: <p>Im trying to add ActiveAdmin to a (massive) application. I follow all the steps here: </p>
  
  <p><a href="https://activeadmin.info/0-installation.html#setting-up-active-admin" rel="nofollow noreferrer">https://activeadmin.info/0-installation.html#setting-up-active-admin</a></p>
  
  <p>The installation process was fine. My problem here is with the assets. When I tried to run: </p>
  
  <p><a href="http://localhost:3000/admin/login/" rel="nofollow noreferrer">http://localhost:3000/admin/login/</a></p>
  
  <p>I got an error: </p>
  
  <pre><code>Showing /Users/fmaymone/.rvm/gems/ruby-2.3.0/gems/activeadmin- 
  1.1.0/app/views/layouts/active_admin_logged_out.html.erb where line #9 raised:
  
  couldn't find file 'jquery3' with type 'application/javascript'
  Checked in these paths: 
  </code></pre>
  
  <p>This application is kind of tricky. Its running webpack together with the rails server. I never worked with this kind of configuration.</p>
  
  <p>Theres not a application.js where I can add a require//</p>
  
  <p>I tried doing a npm i jquery too. </p>
  
  <p>Should I put directly inside the webpack the jquery.js? </p>
  
  <p>This is my GemFile</p>
  
  <pre><code>gem 'rails', '4.2.2'
  
  # This needs to be declared earlier than alphabetical order to load properly re: the app.
  gem 'paperclip', '~&gt; 5.0.0'
  
  
  
  gem 'activeadmin', '~&gt; 1.4', '&gt;= 1.4.3'
  gem 'actionpack-action_caching'
  gem 'active_model-errors_details'
  gem 'active_model_serializers', '~&gt; 0.10.0'
  gem 'activerecord-rescue_from_duplicate'
  gem 'activerecord-sqlserver-adapter', '~&gt; 4.2.0'
  gem 'addressable'
  gem 'ahoy_email'
  gem 'ahoy_matey'
  gem 'airbrake', '~&gt;6.2'
  gem 'ajax-datatables-rails'
  gem 'asset_sync'
  gem 'attachment_on_the_fly'
  gem 'aws-sdk', '~&gt; 2.0'
  gem 'axlsx', '2.1.0.pre'
  gem 'axlsx_rails'
  gem 'blazer'
  gem 'bootstrap-generators', '~&gt; 3.3.4'
  gem 'bootstrap-sass', '~&gt; 3.3.4'
  gem 'browser-timezone-rails'
  gem 'chronic'
  gem 'coffee-rails', '~&gt; 4.1.0'
  gem 'countries'
  gem 'daemons'
  gem 'data_migrate', '~&gt;5.0'
  gem 'delayed_job', '~&gt;4.1.5'
  gem 'delayed_job_active_record'
  gem 'devise'
  gem 'dotenv-rails', :groups =&gt; [:development, :test]
  gem 'double-bag-ftps'
  gem 'faraday'
  gem 'fog-aws'
  gem 'font-awesome-sass', '~&gt; 4.7.0'
  gem 'geocoder', '~&gt; 1.5.1'
  gem 'hashdiff'
  gem 'hashformer'
  gem 'hashie'
  gem 'htmlentities'
  gem 'httparty'
  gem 'hubspot-ruby', '~&gt; 0.4.0'
  gem 'jbuilder', '~&gt; 2.0'
  gem 'jira-ruby'
  gem 'jquery-datatables-rails', github: "rweng/jquery-datatables-rails", branch: "master"
  gem 'jquery-rails'
  gem 'json-schema'
  gem 'kaminari'
  gem 'libv8', '6.7.288.46.1'
  gem 'mailgun-ruby', '~&gt;1.1.6'
  gem 'marketingcloudsdk', '~&gt; 1.0'
  gem 'mini_racer', '0.2.3', platforms: :ruby
  gem 'mjml-rails'
  gem 'money-rails', '~&gt;1'
  gem 'multipart-post'
  gem 'net-scp'
  gem 'newrelic_rpm'
  gem 'oj'
  gem 'oj_mimic_json'
  gem 'pg'
  gem 'progress_bar'
  gem 'rack-cors', :require =&gt; 'rack/cors'
  gem 'rails-observers', '~&gt; 0.1.2'
  gem 'rails_admin', '~&gt; 1.2.0'
  gem 'ransack'
  gem 'react_on_rails', '~&gt;6'
  gem 'rest-client'
  gem 'retriable', '~&gt; 3.1'
  gem 'roo', '~&gt; 2.7.0'
  gem 'roo-xls'
  gem 'rubyzip', '~&gt; 1.1.0'
  gem 'sass-rails', '~&gt; 5.0.6'
  gem 'savon', '~&gt; 2.2.0'
  gem 'schema_plus_pg_indexes'
  gem 'sdoc', '~&gt; 0.4.0', group: :doc
  gem 'seed_dump'
  gem 'simple_form'
  gem 'slither', :git =&gt; 'https://github.com/Programatica/slither.git'
  gem 'stripe'
  gem 'sunspot_rails', '~&gt; 2.2.5'
  gem 'sunspot_solr', '~&gt; 2.2.5'# optional pre-packaged Solr distribution for use in development
  gem 'taxjar-ruby', require: 'taxjar'
  gem 'thin'
  gem 'tiny_tds'
  gem 'twitter-typeahead-rails'
  gem 'uglifier', '&gt;= 1.3.0'
  gem 'validates_timeliness', '~&gt; 4.0'
  gem 'wannabe_bool'
  gem 'whenever', :require =&gt; false
  gem 'wisper', '~&gt; 2.0.0'
  gem 'wisper-rspec', require: false, groups: [:development, :test]
  gem 'workflow'
  gem "graphql"
  gem "graphql-errors"
  gem "graphql-batch"
  gem "graphql-guard"
  gem "nokogiri"
  
  group :production, :staging do
    gem 'sprockets-redirect'
  end
  
  group :test do
    gem 'shoulda-matchers', '~&gt; 3.1', '&gt;= 3.1.1'
    gem 'shoulda-callback-matchers', '~&gt; 1.1.1'
    gem 'simplecov', :require =&gt; false
    gem "vcr"
  end
  
  group :development do
    gem 'web-console', '~&gt; 2.0'
  end
  
  group :development, :test do
    gem "pry"
    gem 'pry-byebug'
    gem "guard-rspec"
    gem 'spring-commands-rspec'
    gem 'graphiql-rails'
    gem "puma"
    gem 'byebug'
    gem 'spring'
    gem 'faker'
    gem 'rspec'
    gem 'rspec-rails'
    gem 'rspec_candy'
    gem 'factory_bot_rails'
    gem 'capybara'
    gem 'database_cleaner'
    gem 'ffaker'
    gem 'to_factory'
    gem 'timecop'
    gem 'test_after_commit', :group =&gt; :test
    gem 'webmock'
  end
  </code></pre>
  
  <p>Thanks</p>