title: Rails Webpacker compile error on Production enviorment
body: <h1>env</h1>
  <pre><code>Rails 6.0.0
  Ruby 2.6.0
  Amazon Linux2
  </code></pre>
  <h1>What</h1>
  <p><img src="https://i.stack.imgur.com/2jNST.png" alt="enter image description here" /></p>
  <p>When I deploy my rails app this error happen</p>
  <pre><code>ActionView::Template::Error (Webpacker can't find application in /home/web/www/eloop-regular/public/packs/manifest.json. Possible causes:
  1. You want to set webpacker.yml value of compile to true for your environment
     unless you are using the `webpack -w` or the webpack-dev-server.
  2. webpack has not yet re-run to reflect updates.
  3. You have misconfigured Webpacker's config/webpacker.yml file.
  4. Your webpack configuration is not creating a manifest.
  
  </code></pre>
  <h2>1. You want to set webpacker.yml value of compile to true for your environment unless you are using the <code>webpack -w</code> or the webpack-dev-server.</h2>
  <p>my config/webpacker.yml contains</p>
  <pre><code>production:
    &lt;&lt;: *default
  
    # Production depends on precompilation of packs prior to booting for performance.
    compile: true
  
    # Extract and emit a css file
    extract_css: true
  
    # Cache manifest.json for performance
    cache_manifest: true
  </code></pre>
  <h2>2. webpack has not yet re-run to reflect updates.</h2>
  <p>I run</p>
  <pre><code>$ RAILS_ENV=production bundle exec rails webpacker:compile
  </code></pre>
  <h2>3. You have misconfigured Webpacker's config/webpacker.yml file.</h2>
  <p>in development environment webpacker works correctly.</p>
  <h2>4. Your webpack configuration is not creating a manifest.</h2>
  <p>manifest.json is created</p>