Fix security guide captcha 03 21 2015 [ci skip]

Tiny optimization of http auth Realm unquoting

Use #prepend rather than using 2 aliases

Sidekiq::CLI#boot_system require "#{dummy_app_path}/config/environment.rb".
But this file has already been required in'test/support/integration/helper.rb'.
This patch will change to use Sidekiq::Launcher directly.

Removing GZip section since Sprockets 3.0 no longer create .gz files

- https://github.com/rails/sprockets/commit/14b3b2eddac4699c64c051888e3801732b9a4418
- https://github.com/rails/sprockets/issues/26

Set default form builder for a controller

When 7e504927 was merged setting `Encoding.default_internal` and
`Encoding.default_external` would throw a warning when the ActionPack
tests were run.

Example warning: `actionpack/test/dispatch/static_test.rb:12: warning:
setting Encoding.default_external`

This patch silences the warnings as other similar tests do for setting
default_internal and default_external.

fix indent in routes when using namespaced controllers

Add support for Set to Relation#where

Use Ruby 2.2.2 on travis

Upgrade to Ruby 2.2.2

This is required to run https://github.com/rails/rails/pull/19752 successfully.

Previously `#where` used to treat `Set`objects as nil, but now it treats
them as an array:

  set = Set.new([1, 2])
  Author.where(:id => set)
  # => SELECT "authors".* FROM "authors" WHERE "authors"."id" IN (1, 2)

and fix the grammar in the ruby_version_check.rb user message.

Before:

  namespace :foo do
  namespace :bar do
    get 'baz/index'
    end
  end

After:

  namespace :foo do
    namespace :bar do
      get 'baz/index'
    end
  end

Fix the wrong documentation about config.autoload_paths [ci skip]

Related to f1af967e. [ci skip]

config.autoload_paths is not changeable from environment specific configuration files.

Document that partial indexes are only supported by Postgres and SQLite.

Fixes #18106

specifically are checked for CSRF, when dealing with the browser.

[ci skip]

We should document current behavior, and this is design of API for now.

Closes #17597

Thanks for patch @sgrif :trollface:

Closes #18216

This reverts commit d2156203, reversing
changes made to bbbbfe1a.

Closes #19492 and fixes #19453

Documentation is giving an example that can be replaced by a more dry command.
Give a hint that ids can be used instead of pluck(:id).

[skip ci] Fix counter_cache in the Rails Guides