Enable public file server for assets

Attempt to deal with https://app.fizzy.do/5986089/cards/2790

config/environments/production.rb

@@ -20,8 +20,10 @@ Rails.application.configure do
   # key such as config/credentials/production.key. This key is used to decrypt credentials (and other encrypted files).
   # config.require_master_key = true
 
-  # Disable serving static files from `public/`, relying on NGINX/Apache to do so instead.
-  # config.public_file_server.enabled = false
+  config.public_file_server.enabled = true
+  config.public_file_server.headers = {
+    "Cache-Control" => "public, max-age=#{1.year.to_i}"
+  }
 
   # Enable serving of images, stylesheets, and JavaScripts from an asset server.
   # config.asset_host = "http://assets.example.com"