Add/configure ActiveStorage

config/environments/production.rb

@@ -110,6 +110,10 @@ Rails.application.configure do
   # Set this to true and configure the email server for immediate delivery to raise delivery errors.
   config.action_mailer.raise_delivery_errors = true
 
+  # TODO make configurable
+  # Store attachments in S3-compatible back-end
+  config.active_storage.service = :local
+
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation cannot be found).
   config.i18n.fallbacks = true