Move assets precompile (and version) to an initializer

sprockets-rails 2.1 needs the precompile list to be available in all
environments.

guides/source/asset_pipeline.md

@@ -709,17 +709,17 @@ JS/CSS is excluded, as well as raw JS/CSS files; for example, `.coffee` and
 `.scss` files are **not** automatically included as they compile to JS/CSS.
 
 If you have other manifests or individual stylesheets and JavaScript files to
-include, you can add them to the `precompile` array in `config/application.rb`:
+include, you can add them to the `precompile` array in `config/initializers/assets.rb`:
 
 ```ruby
-config.assets.precompile += ['admin.js', 'admin.css', 'swfObject.js']
+Rails.application.config.assets.precompile += ['admin.js', 'admin.css', 'swfObject.js']
 ```
 
 Or, you can opt to precompile all assets with something like this:
 
 ```ruby
-# config/application.rb
-config.assets.precompile << Proc.new do |path|
+# config/initializers/assets.rb
+Rails.application.config.assets.precompile << Proc.new do |path|
   if path =~ /\.(css|js)\z/
     full_path = Rails.application.assets.resolve(path).to_path
     app_assets_path = Rails.root.join('app', 'assets').to_path

railties/CHANGELOG.md

+*   Move configuration of asset precompile list and version to an initializer.
+
+    *Matthew Draper*
+
 *   Do not set the Rails environment to test by default when using test_unit Railtie.
 
     *Konstantin Shabanov*

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -231,6 +231,12 @@ def delete_js_folder_skipping_javascript
         end
       end
 
+      def delete_assets_initializer_skipping_sprockets
+        if options[:skip_sprockets]
+          remove_file 'config/initializers/assets.rb'
+        end
+      end
+
       def finish_template
         build(:leftovers)
       end

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

@@ -33,12 +33,7 @@ Rails.application.configure do
   # Generate digests for assets URLs.
   config.assets.digest = true
 
-  # Version of your assets, change this if you want to expire all your assets.
-  config.assets.version = '1.0'
-
-  # Precompile additional assets.
-  # application.js, application.css, and all non-JS/CSS in app/assets folder are already added.
-  # config.assets.precompile += %w( search.js )
+  # `config.assets.precompile` has moved to config/initializers/assets.rb
   <%- end -%>
 
   # Specifies the header that your server uses for sending files.

railties/lib/rails/generators/rails/app/templates/config/initializers/assets.rb.tt

+# Be sure to restart your server when you modify this file.
+
+# Version of your assets, change this if you want to expire all your assets.
+Rails.application.config.assets.version = '1.0'
+
+# Precompile additional assets.
+# application.js, application.css, and all non-JS/CSS in app/assets folder are already added.
+# Rails.application.config.assets.precompile += %w( search.js )

railties/test/generators/app_generator_test.rb

@@ -237,6 +237,7 @@ def test_generator_if_skip_action_view_is_given
 
   def test_generator_if_skip_sprockets_is_given
     run_generator [destination_root, "--skip-sprockets"]
+    assert_no_file "config/initializers/assets.rb"
     assert_file "config/application.rb" do |content|
       assert_match(/#\s+require\s+["']sprockets\/railtie["']/, content)
     end
@@ -252,7 +253,6 @@ def test_generator_if_skip_sprockets_is_given
       assert_no_match(/config\.assets\.digest = true/, content)
       assert_no_match(/config\.assets\.js_compressor = :uglifier/, content)
       assert_no_match(/config\.assets\.css_compressor = :sass/, content)
-      assert_no_match(/config\.assets\.version = '1\.0'/, content)
     end
   end