This makes "sprockets/railtie" explicit. This means that sprockets will
be loaded when you require "rails/all". If you are not using requiring
"rails/all", you need to manually load it with all other framework
railties.

In order to be complete, this commit also adds --skip-sprockets to
the rails generator.

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Set only helpers_path on inherited hook in action_controller/railtie.rb and use helper(:all) just after that

This change is needed, because we must take namespace into account and if
controller's/mailer's class is namespaced, engine's paths should be set
instead of application's ones.

The nice side effect of this is removing unneeded logic in
ActionController::Base.inherited - now the helpers_path should be set
correctly even for engine's controllers, so helper(:all) will always
include correct helpers.

Move ActionController::Railties::RoutesHelpers and ActionMailer::Railties::RoutesHelper to AbstractController::Railties::RoutesHelpers

Include application's helpers and router helpers by default, but include engine's ones for controllers inside isolated namespace

mounted_helpers are a bit similar to url_helpers. They're automatically
included in controllers for Rails.application and each of mounted
Engines. Mounted helper allows to call url_for and named helpers for
given application.

Given Blog::Engine mounted as blog_engine, there are 2 helpers defined:
app and blog_engine. You can call routes for app and engine using those
helpers:

app.root_url
app.url_for(:controller => "foo")
blog_engine.posts_path
blog_engine.url_for(@post)

The former should be symmetric with ancestors and include all children. However, it should not include self since ancestors + descendants should not have duplicated. The latter is symmetric to superclass in the sense it only includes direct children.

By adopting a convention, we expect to have less conflict with other frameworks, as Datamapper. For this moment, to ensure ActiveModel::Validations can be used with Datamapper, we should always call ActiveSupport::DescendantsTracker.descendants(self) internally instead of self.descendants avoiding conflicts.

Move Rails::LogSubscriber to ActiveSupport::LogSubscriber, allowing frameworks like ActiveRecord and ActiveResource to log outsude Rails::Application [#4816 state:resolved]

Clean up the config object in ActionPack. Create config_accessor which just delegates to the config object, reducing the number of deprecations and add specific tests.

Fix a bug in ActionDispatch::Static where Rails cannot find assets if started in another directory which is not the RAILS_ROOT.

Rename config.cookie_secret to config.secret_token and pass it as configuration in request.env. This is another step forward removing global configuration.

should run during framework load do:

ActiveSupport.on_load(:action_controller) do
  # Code run in the context of AC::Base
end

Move application configuration to the application configuration object, remove railtie_name and engine_name and allow to set the configuration object.

	This is an interim solution pending revisiting the rails
	framework configuration situation. 

add lazy_load_hooks.rb, which allows us to declare code that
should be run at some later time. For instance, this allows
us to defer requiring ActiveRecord::Base at boot time purely
to apply configuration. Instead, we register a hook that should
apply configuration once ActiveRecord::Base is loaded.

With these changes, brings down total boot time of a
new app to 300ms in production and 400ms in dev.

TODO: rename base_hook

Get rid of relative_url_path in favor of respecting SCRIPT_NAME. Also added a way to specify a default SCRIPT_NAME when generating URLs out of the context of a request.

Deprecated ActionController::Base.session_options= and ActionController::Base.session_store= in favor of a config.session_store method (which takes params) and a config.cookie_secret variable, which is used in various secret scenarios. The old AC::Base options will continue to work with deprecation warnings.

Remove traces of SharedTestRoutes from user code; leave it as a standin for Rails.application.routes in Rails internal tests