Include default storage configuration

railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt

@@ -26,6 +26,9 @@ Rails.application.configure do
 
     config.cache_store = :null_store
   end
+
+  # Store uploaded files on the local file system (see config/storage_services.yml for options)
+  config.active_storage.service = :local
   <%- unless options.skip_action_mailer? -%>
 
   # Don't care if the mailer can't send.

railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt

@@ -45,6 +45,8 @@ Rails.application.configure do
   # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
   # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
 
+  # Store uploaded files on the local file system (see config/storage_services.yml for options)
+  config.active_storage.service = :local
   <%- unless options[:skip_action_cable] -%>
   # Mount Action Cable outside main process or domain
   # config.action_cable.mount_path = nil

railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt

@@ -27,6 +27,9 @@ Rails.application.configure do
 
   # Disable request forgery protection in test environment.
   config.action_controller.allow_forgery_protection = false
+
+  # Store uploaded files on the local file system in a temporary directory
+  config.active_storage.service = :test
   <%- unless options.skip_action_mailer? -%>
   config.action_mailer.perform_caching = false
 

railties/lib/rails/generators/rails/app/templates/config/storage_services.yml

@@ -0,0 +1,27 @@
+test:
+  service: Disk
+  root: <%= Rails.root.join("tmp/storage") %>
+
+local:
+  service: Disk
+  root: <%= Rails.root.join("storage") %>
+
+# Use rails secrets:edit to set the AWS secrets (as shared:aws:access_key_id|secret_access_key)
+# amazon:
+#   service: S3
+#   access_key_id: <%= Rails.application.secrets.dig(:aws, :access_key_id) %>
+#   secret_access_key: <%= Rails.application.secrets.dig(:aws, :secret_access_key) %>
+#   region: us-east-1
+#   bucket: your_own_bucket
+
+# Remember not to checkin your GCS keyfile to a repository
+# google:
+#   service: GCS
+#   project: your_project
+#   keyfile: <%= Rails.root.join("path/to/gcs.keyfile") %>
+#   bucket: your_own_bucket
+
+# mirror:
+#   service: Mirror
+#   primary: local
+#   secondaries: [ amazon, google ]

railties/test/generators/app_generator_test.rb

@@ -64,6 +64,7 @@
   config/routes.rb
   config/secrets.yml
   config/spring.rb
+  config/storage_services.yml
   db
   db/seeds.rb
   lib