I put a more up-to-date description of Web Console in the release notes.
I'm not really happy with the language, so if you guys can help me with
that I'll be grateful :)

[skip ci]

See http://guides.rubyonrails.org/api_documentation_guidelines.html#wording

Related: https://github.com/rails/rails/pull/16607

Remove duplicate line in Railties.

[ci skip]

Remove ActiveRecord config instructions for active_record.attribute_types_cached_by_default, which was removed in https://github.com/rails/rails/commit/66736c8e50585

Point release notes to stable branch for list of commits. [ci skip]

Point release notes to stable branch for list of commits. [ci skip]

This reverts commit 699babe8.

Also change the upgrading_ruby_on_rails link back to original in 4_2_release_notes.

[Godfrey Chan, Genadi Samokovarov]

Previously setting simple values to the config.x object resulted in the
following:

    config.x.super_debugger = true
    config.x.super_debugger #=> {}

Which was against the examples showed in the changelog/release notes.

Godfrey Chan, Genadi Samokovarov

This reverts commit de489134.

Conflicts:
	railties/lib/rails/railtie/configuration.rb

It added regression. Will be back after the beta

Mention the web-console inclusion in the default Gemfile in the Release
notes and the railties changelog. We can eventually mention it in the
upgrade guide, if needed.

[ci skip]

1. Hashes can be assigned
2. We don't need a special level anymore

The method chain only works in the top level.

If users need a second level they need to assign a OrderedOptions to the
key:

    config.resque.server = ActiveSupport::OrderedOptions.new
    config.resque.server.url = "http://localhost"
    config.resque.server.port = 3000

[Rafael Mendonça França + Carlos Antonio da Silva]