Fix link in 'Configuring Rails Applications' [ci skip]

Fix link in 'Ruby on Rails 3.0 Release Notes' [ci skip]

Fix markdown syntax in 'Ruby on Rails 2.2 Release Notes' [ci skip]

[ci skip] Release notes: Add PR #24866 to release notes

Implement helpers proxy in controller instance level

Active Model: Improve CHANGELOG and documentation for `validates_acceptance_of` [ci skip]

Expand on Action Mailer Fragment caching tests

- Improve CHANGELOG entry for #18439.
- The documentation is updated as per changes in PR #18439 to the
  `accept` option.
- The explanation about the virtual attribute is moved at the end so
  that the arity of `accept` option is explained first.
- Added a note that `message` can also be passed to `validates_acceptance_of`.

Followup of #18322

It is a common pattern in the Rails community that when people want to
:xa
use any kind of helper that is defined inside app/helpers they includes
the helper module inside the controller like:

    module UserHelper
      def my_user_helper
        # ...
      end
    end

    class UsersController < ApplicationController
      include UserHelper

      def index
        render inline: my_user_helper
      end
    end

This has problem because the helper can't access anything that is
defined in the view level context class.

Also all public methods of the helper become available in the controller
what can lead to undesirable methods being routed and behaving as
actions.

Also if you helper depends on other helpers or even Action View helpers
you need to include each one of these dependencies in your controller
otherwise your helper is not going to work.

We already have a helpers proxy at controller class level but that proxy
doesn't have access to the instance variables defined in the
controller.

With this new instance level helper proxy users can reuse helpers in the
controller without having to include the modules and with access to
instance variables defined in the controller.

    class UsersController < ApplicationController
      def index
        render inline: helpers.my_user_helper
      end
    end

Change to use a more realistic example [ci skip]

delegate encode_with instead of to_yaml, which is deprecated

Change to use a more realistic example and not giving the impression that destroy_all is preferred way to destroy related records.
This example just wants to demonstrate callback behaviour.

[ci skip]

Remove extra space [ci skip]

There were a lot of protected instance variables in
AbsctractController::Rendering that were related to Action Controller
and Action View.

Moving to ActionController::Base's protected instance list we make it
closer to where they are really defined.

After fb898e98, the `before_destroy` had some code that used
SQL interpolation left over. Don't think we should promote
that even if the values aren't directly from user input.

do not pass conditions to `#destroy_all` [ci skip]

Passing conditions to `#destroy_all` was deprecated in c82c5f8f.

Run Active Support tests in both `to_time` modes

Add to the matrix of Travis tests an entry that runs the Active Support
tests when `ActiveSupport.to_time_preserves_timezone = true`.

These two tests are explicitly testing that to_time is returning times
with the sytem timezone's UTC offset, therefore they will fail when
running them with `ActiveSupport.to_time_preserves_timezone = true`.

The to_yaml method is undefined when running the test as:

  $ ruby -I lib:test test/core_ext/string_ext_test.rb

Doesn't fail when running rake test:isolated presumably because
something else has required 'yaml' already.

Ensure compatibility between ActionDispatch::Request::Session and Rack

Adding the `each` method is required for ensuring compatibility between
Rails, and other Rack frameworks (like Sinatra, etc.), that are mounted
within Rails, and wish to use its session tooling. Prior to this, there
was an inconsistency between ActionDispatch::Request::Session and
Rack::Session::Cookie, due to the absence of the `each` method. This
should hopefully fix that error. :)

For a full integration test with Sinatra and a standalone Rack
application, you can check out the gist for that here: https://gist.github.com/maclover7/08cd95b0bfe259465314311941326470.

Solves #15843.

Bump Ruby versions

Fix some typos in comments [ci skip]

[ci skip]

2.2.4 --> 2.2.5
2.3.0 --> 2.3.1

This is an engine living in action_cable/engine.rb, convention is to
call these things *::Engine.

Looking at thi git history looks like the current *::Railtie was just
an accident.

Fix actionpack typos [ci skip]

Depend on bundler 1.11.2 on travis until bundle update discrepancy is solved on 1.12.x

Fix failing tests