Explain the manifest link better and hide by default

Author: dhh

railties/lib/rails/generators/rails/app/templates/app/views/layouts/application.html.erb.tt

@@ -10,7 +10,9 @@
 
     <%%= yield :head %>
 
-    <!-- link rel="manifest" href="/manifest.json" -->
+    <%%# Enable PWA manifest for installable apps (make sure to enable in config/routes.rb too!) %>
+    <%%#= tag.link rel: "manifest", href: pwa_manifest_path %>
+
     <link rel="icon" href="/icon.png" type="image/png">
     <link rel="icon" href="/icon.svg" type="image/svg+xml">
     <link rel="apple-touch-icon" href="/icon.png">

railties/lib/rails/generators/rails/app/templates/config/routes.rb.tt

@@ -7,8 +7,8 @@ Rails.application.routes.draw do
 
   <%- unless options.api? -%>
   # Render dynamic PWA files from app/views/pwa/* (remember to link manifest in application.html.erb)
-  # get "service-worker" => "rails/pwa#service_worker", as: :pwa_service_worker
   # get "manifest" => "rails/pwa#manifest", as: :pwa_manifest
+  # get "service-worker" => "rails/pwa#service_worker", as: :pwa_service_worker
 
   <%- end -%>
   # Defines the root path route ("/")