Sprockets::Rails::Helper::AssetNotPrecompiled in が出てコケた #Rails

環境

Rails 5.2.3

次のエラーが出た

ctionView::Template::Error (Asset `application.css` was not declared to be precompiled in production.
Declare links to your assets in `app/assets/config/manifest.js`.

  //= link application.css
and restart your server):
    4:     <title>hogehogeapp</title>
    5:     <%= csrf_meta_tags %>
    6:     <%= csp_meta_tag %>
    7:     <%= stylesheet_link_tag "application", :media => "all" %>
    8:   </head>
    9:   <body>
   10:     <nav class="navbar navbar-expand navbar-dark bg-success" >

app/views/layouts/application.html.erb:7:in `_app_views_layouts_application_html_erb__823627666839579830_70158635396840'

なので
assets.rbに追記して

config/initializers/assets.rb

#省略
Rails.application.config.assets.precompile += %w( application.css )
#省略

次のコマンドを実行

$rake assets:precompile

あとは

$rails s

で起動した。

完全にメモ、あとで気が向けば追記

おしまい