Make this a suggestion instead of a default

Otherwise Chrome is going to prompt automatically to install the app as
a web app. Thats a bit too much out of the box.

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/*
- 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
+ # get "manifest" => "rails/pwa#manifest", as: :pwa_manifest
 
  <%- end -%>
  # Defines the root path route ("/")