18 files changed, 192 insertions, 91 deletions
diff --git a/guides/source/4_1_release_notes.md b/guides/source/4_1_release_notes.md
index 52a5acb75e..c7877a9cb5 100644
--- a/guides/source/4_1_release_notes.md
+++ b/guides/source/4_1_release_notes.md
@@ -136,7 +136,7 @@ end
 
 ### Action Mailer Previews
 
-Action Mailer previews provide a way to visually see how emails look by visiting
+Action Mailer previews provide a way to see how emails look by visiting
 a special URL that renders them.
 
 You implement a preview class whose methods return the mail object you'd like
diff --git a/guides/source/4_2_release_notes.md b/guides/source/4_2_release_notes.md
index a598c7c319..8553cffa9d 100644
--- a/guides/source/4_2_release_notes.md
+++ b/guides/source/4_2_release_notes.md
@@ -49,13 +49,13 @@ bog down the controller or model.
 The new GlobalID library makes it easy to pass Active Record objects to jobs by
 serializing them in a generic form. This means you no longer have to manually
 pack and unpack your Active Records by passing ids. Just give the job the
-straight Active Record object, and it'll serialize it using GlobalID, and
-deserialize it at run time.
+Active Record object, and it'll serialize it using GlobalID, and deserialize
+it at run time.
 
 ### Adequate Record
 
 Adequate Record is a set of refactorings that make Active Record `find` and
-`find_by` methods and some association queries upto 2x faster.
+`find_by` methods and some association queries up to 2x faster.
 
 It works by caching SQL query patterns while executing the Active Record calls.
 The cache helps skip parts of the computation involved in the transformation of
@@ -88,7 +88,7 @@ The caching is not used in the following scenarios:
   Post.find [1,2]
   ```
 
-- `find_by` with sql fragments:
+- `find_by` with SQL fragments:
 
   ```ruby
   Post.find_by "published_at < ?", 2.weeks.ago
@@ -196,9 +196,9 @@ end
 Due to a [change in Rack](https://github.com/rack/rack/commit/28b014484a8ac0bbb388e7eaeeef159598ec64fc),
 `rails server` now listens on `localhost` instead of `0.0.0.0` by default. This
 should have minimal impact on the standard development workflow as both http://127.0.0.1:3000
-and http://localhost:3000 would continue to work as before on your own machine.
+and http://localhost:3000 will continue to work as before on your own machine.
 
-However, with this change you would no longer be able to access the Rails server
+However, with this change you will no longer be able to access the Rails server
 from a different machine (e.g. your development environment is in a virtual
 machine and you would like to access it from the host machine), you would need
 to start the server with `rails server -b 0.0.0.0` to restore the old behavior.
@@ -300,6 +300,9 @@ Please refer to the [Changelog][railties] for detailed changes.
 
 ### Removals
 
+*   The `--skip-action-view` option has been removed from the
+    app generator. ([Pull Request](https://github.com/rails/rails/pull/17042))
+
 *   The `rails application` command has been removed without replacement.
     ([Pull Request](https://github.com/rails/rails/pull/11616))
 
@@ -358,9 +361,9 @@ Please refer to the [Changelog][railties] for detailed changes.
 
     ([Pull Request](https://github.com/rails/rails/pull/16129))
 
-*   Introduced a `--skip-gems` option in the app generator to skip gems such as
-    `turbolinks` and `coffee-rails` that do not have their own specific flags.
-    ([Commit](https://github.com/rails/rails/commit/10565895805887d4faf004a6f71219da177f78b7))
+*   Introduce a `--skip-turbolinks` option in the app generator to not generate
+    any turbolinks integration.
+    ([Commit](https://github.com/rails/rails/commit/bf17c8a531bc8059d50ad731398002a3e7162a7d))
 
 *   Introduced a `bin/setup` script to enable automated setup code when
     bootstrapping an application.
@@ -395,6 +398,9 @@ Please refer to the [Changelog][action-pack] for detailed changes.
 
 ### Deprecations
 
+*   Deprecated the `only_path` option on `*_path` helpers.
+    ([Commit](https://github.com/rails/rails/commit/aa1fadd48fb40dd9396a383696134a259aa59db9))
+
 *   Deprecated `assert_tag`, `assert_no_tag`, `find_tag` and `find_all_tag` in
     favor of `assert_select`.
     ([Commit](https://github.com/rails/rails-dom-testing/commit/b12850bc5ff23ba4b599bf2770874dd4f11bf750))
@@ -468,7 +474,7 @@ Please refer to the [Changelog][action-pack] for detailed changes.
     ([Pull Request](https://github.com/rails/rails/pull/14280))
 
 *   When the Rails server is set to serve static assets, gzip assets will now be
-    served if the client supports it and a pre-generated gzip file (.gz) is on disk.
+    served if the client supports it and a pre-generated gzip file (`.gz`) is on disk.
     By default the asset pipeline generates `.gz` files for all compressible assets.
     Serving gzip files minimizes data transfer and speeds up asset requests. Always
     [use a CDN](http://guides.rubyonrails.org/asset_pipeline.html#cdns) if you are
@@ -476,7 +482,7 @@ Please refer to the [Changelog][action-pack] for detailed changes.
     ([Pull Request](https://github.com/rails/rails/pull/16466))
 
 *   The way `assert_select` works has changed; specifically a different library
-    is used to interpret css selectors, build the transient DOM that the
+    is used to interpret CSS selectors, build the transient DOM that the
     selectors are applied against, and to extract the data from that DOM. These
     changes should only affect edge cases. Examples:
     *  Values in attribute selectors may need to be quoted if they contain
@@ -534,7 +540,7 @@ Please refer to the [Changelog][action-mailer] for detailed changes.
 *   Deprecated `*_path` helpers in mailers. Always use `*_url` helpers instead.
     ([Pull Request](https://github.com/rails/rails/pull/15840))
 
-*   Deprecated `deliver` / `deliver!` in favour of `deliver_now` / `deliver_now!`.
+*   Deprecated `deliver` / `deliver!` in favor of `deliver_now` / `deliver_now!`.
     ([Pull Request](https://github.com/rails/rails/pull/16582))
 
 ### Notable changes
@@ -572,6 +578,10 @@ Please refer to the [Changelog][active-record] for detailed changes.
 
 ### Deprecations
 
+*   Deprecated `sanitize_sql_hash_for_conditions` without replacement. Using a
+    `Relation` for performing queries and updates is the prefered API.
+    ([Commit](https://github.com/rails/rails/commit/d5902c9e))
+
 *   Deprecated swallowing of errors inside `after_commit` and `after_rollback`.
     ([Pull Request](https://github.com/rails/rails/pull/16537))
 
@@ -593,7 +603,7 @@ Please refer to the [Changelog][active-record] for detailed changes.
     ([Pull Request](https://github.com/rails/rails/pull/15704))
 
 *   Deprecated returning `nil` from `column_for_attribute` when no column
-    exists. It will return a null object in Rails 5.0
+    exists. It will return a null object in Rails 5.0.
     ([Pull Request](https://github.com/rails/rails/pull/15878))
 
 *   Deprecated using `.joins`, `.preload` and `.eager_load` with associations
@@ -645,7 +655,7 @@ Please refer to the [Changelog][active-record] for detailed changes.
     ([Commit](https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d))
 
 *   `ActiveRecord::Dirty` now detects in-place changes to mutable values.
-    Serialized attributes on ActiveRecord models will no longer save when
+    Serialized attributes on Active Record models will no longer save when
     unchanged. This also works with other types such as string columns and json
     columns on PostgreSQL.
     (Pull Requests [1](https://github.com/rails/rails/pull/15674),
@@ -755,6 +765,10 @@ Please refer to the [Changelog][active-support] for detailed changes.
     to `:sorted` but will be changed to `:random` in Rails 5.0.
     ([Commit](https://github.com/rails/rails/commit/53e877f7d9291b2bf0b8c425f9e32ef35829f35b))
 
+*   `Object#try` and `Object#try!` can now be used without an explicit receiver.
+    ([Commit](https://github.com/rails/rails/commit/5e51bdda59c9ba8e5faf86294e3e431bd45f1830),
+    [Pull Request](https://github.com/rails/rails/pull/17361))
+
 *   The `travel_to` test helper now truncates the `usec` component to 0.
     ([Commit](https://github.com/rails/rails/commit/9f6e82ee4783e491c20f5244a613fdeb4024beb5))
 
diff --git a/guides/source/_welcome.html.erb b/guides/source/_welcome.html.erb
index f84f1cb376..f2315bfe22 100644
--- a/guides/source/_welcome.html.erb
+++ b/guides/source/_welcome.html.erb
@@ -15,5 +15,5 @@
 </p>
 <% end %>
 <p>
-  The guides for earlier releases: <a href="http://guides.rubyonrails.org/v4.1.4/">Rails 4.1.4</a>, <a href="http://guides.rubyonrails.org/v4.0.8/">Rails 4.0.8</a>, <a href="http://guides.rubyonrails.org/v3.2.19/">Rails 3.2.19</a> and <a href="http://guides.rubyonrails.org/v2.3.11/">Rails 2.3.11</a>.
+  The guides for earlier releases: <a href="http://guides.rubyonrails.org/v4.1.6/">Rails 4.1.6</a>, <a href="http://guides.rubyonrails.org/v4.0.10/">Rails 4.0.10</a>, <a href="http://guides.rubyonrails.org/v3.2.19/">Rails 3.2.19</a> and <a href="http://guides.rubyonrails.org/v2.3.11/">Rails 2.3.11</a>.
 </p>
diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md
index 8890ea453e..1ca0d9ed55 100644
--- a/guides/source/action_controller_overview.md
+++ b/guides/source/action_controller_overview.md
@@ -1213,12 +1213,12 @@ Create the controller and views.
 * `app/views`
 
   ```
-    errors/
-      not_found.html.erb
-      unprocessable_entity.html.erb
-      server_error.html.erb
-    layouts/
-      error.html.erb
+  errors/
+    not_found.html.erb
+    unprocessable_entity.html.erb
+    server_error.html.erb
+  layouts/
+    error.html.erb
   ```
 
 Do not forget to set the correct status code on the controller as shown before.
diff --git a/guides/source/active_job_basics.md b/guides/source/active_job_basics.md
index 9c34418fab..ca851371a9 100644
--- a/guides/source/active_job_basics.md
+++ b/guides/source/active_job_basics.md
@@ -41,10 +41,12 @@ This section will provide a step-by-step guide to creating a job and enqueuing i
 ### Create the Job
 
 Active Job provides a Rails generator to create jobs. The following will create a
-job in `app/jobs`:
+job in `app/jobs` (with an attached test case under `test/jobs`):
 
 ```bash
 $ bin/rails generate job guests_cleanup
+invoke  test_unit
+create    test/jobs/guests_cleanup_job_test.rb
 create  app/jobs/guests_cleanup_job.rb
 ```
 
@@ -52,7 +54,6 @@ You can also create a job that will run on a specific queue:
 
 ```bash
 $ bin/rails generate job guests_cleanup --queue urgent
-create  app/jobs/guests_cleanup_job.rb
 ```
 
 As you can see, you can generate jobs just like you use other generators with
@@ -78,15 +79,18 @@ end
 Enqueue a job like so:
 
 ```ruby
-MyJob.perform_later record  # Enqueue a job to be performed as soon the queueing system is free.
+# Enqueue a job to be performed as soon the queueing system is free.
+MyJob.perform_later record
 ```
 
 ```ruby
-MyJob.set(wait_until: Date.tomorrow.noon).perform_later(record)  # Enqueue a job to be performed tomorrow at noon.
+# Enqueue a job to be performed tomorrow at noon.
+MyJob.set(wait_until: Date.tomorrow.noon).perform_later(record)
 ```
 
 ```ruby
-MyJob.set(wait: 1.week).perform_later(record) # Enqueue a job to be performed 1 week from now.
+# Enqueue a job to be performed 1 week from now.
+MyJob.set(wait: 1.week).perform_later(record)
 ```
 
 That's it!
@@ -108,9 +112,9 @@ see the API Documentation for [ActiveJob::QueueAdapters](http://api.rubyonrails.
 You can easily change your queueing backend:
 
 ```ruby
-# be sure to have the adapter gem in your Gemfile and follow the adapter specific
-# installation and deployment instructions
-Rails.application.config.active_job.queue_adapter = :sidekiq
+# be sure to have the adapter gem in your Gemfile and follow
+# the adapter specific installation and deployment instructions
+config.active_job.queue_adapter = :sidekiq
 ```
 
 
@@ -149,15 +153,38 @@ end
 # environment
 ```
 
-If you want more control on what queue a job will be run you can pass a :queue
-option to #set:
+The default queue name prefix delimiter is '_'.  This can be changed by setting
+`config.active_job.queue_name_delimiter` in `application.rb`:
+
+```ruby
+# config/application.rb
+module YourApp
+  class Application < Rails::Application
+    config.active_job.queue_name_prefix = Rails.env
+    config.active_job.queue_name_delimiter = '.'
+  end
+end
+
+# app/jobs/guests_cleanup.rb
+class GuestsCleanupJob < ActiveJob::Base
+  queue_as :low_priority
+  #....
+end
+
+# Now your job will run on queue production.low_priority on your
+# production environment and on staging.low_priority on your staging
+# environment
+```
+
+If you want more control on what queue a job will be run you can pass a `:queue`
+option to `#set`:
 
 ```ruby
 MyJob.set(queue: :another_queue).perform_later(record)
 ```
 
-To control the queue from the job level you can pass a block to queue_as. The
-block will be executed in the job context (so you can access self.arguments)
+To control the queue from the job level you can pass a block to `#queue_as`. The
+block will be executed in the job context (so you can access `self.arguments`)
 and you must return the queue name:
 
 ```ruby
@@ -179,7 +206,6 @@ end
 ProcessVideoJob.perform_later(Video.last)
 ```
 
-
 NOTE: Make sure your queueing backend "listens" on your queue name. For some
 backends you need to specify the queues to listen to.
 
@@ -240,12 +266,13 @@ UserMailer.welcome(@user).deliver_later
 
 GlobalID
 --------
+
 Active Job supports GlobalID for parameters. This makes it possible to pass live
 Active Record objects to your job instead of class/id pairs, which you then have
 to manually deserialize. Before, jobs would look like this:
 
 ```ruby
-class TrashableCleanupJob
+class TrashableCleanupJob < ActiveJob::Base
   def perform(trashable_class, trashable_id, depth)
     trashable = trashable_class.constantize.find(trashable_id)
     trashable.cleanup(depth)
@@ -256,14 +283,14 @@ end
 Now you can simply do:
 
 ```ruby
-class TrashableCleanupJob
+class TrashableCleanupJob < ActiveJob::Base
   def perform(trashable, depth)
     trashable.cleanup(depth)
   end
 end
 ```
 
-This works with any class that mixes in `ActiveModel::GlobalIdentification`, which
+This works with any class that mixes in `GlobalID::Identification`, which
 by default has been mixed into Active Model classes.
 
 
diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md
index ecf3483d7e..bd074d0055 100644
--- a/guides/source/active_record_basics.md
+++ b/guides/source/active_record_basics.md
@@ -31,7 +31,7 @@ Object Relational Mapping system.
 in his book _Patterns of Enterprise Application Architecture_. In
 Active Record, objects carry both persistent data and behavior which
 operates on that data. Active Record takes the opinion that ensuring
-data access logic is part of the object will educate users of that
+data access logic as part of the object will educate users of that
 object on how to write to and read from the database.
 
 ### Object Relational Mapping
diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md
index 229c6ee458..c8a31fe7b8 100644
--- a/guides/source/active_record_migrations.md
+++ b/guides/source/active_record_migrations.md
@@ -466,7 +466,7 @@ add_foreign_key :articles, :authors
 ```
 
 This adds a new foreign key to the `author_id` column of the `articles`
-table. The key references the `id` column of the `articles` table. If the
+table. The key references the `id` column of the `authors` table. If the
 column names can not be derived from the table names, you can use the
 `:column` and `:primary_key` options.
 
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
index 1c1b863fe9..546c0608ee 100644
--- a/guides/source/active_record_validations.md
+++ b/guides/source/active_record_validations.md
@@ -427,7 +427,7 @@ class Essay < ActiveRecord::Base
   validates :content, length: {
     minimum: 300,
     maximum: 400,
-    tokenizer: lambda { |str| str.scan(/\w+/) },
+    tokenizer: lambda { |str| str.split(/\s+/) },
     too_short: "must have at least %{count} words",
     too_long: "must have at most %{count} words"
   }
@@ -533,6 +533,7 @@ validates :boolean_field_name, presence: true
 validates :boolean_field_name, inclusion: { in: [true, false] }
 validates :boolean_field_name, exclusion: { in: [nil] }
 ```
+
 By using one of these validations, you will ensure the value will NOT be `nil`
 which would result in a `NULL` value in most cases.
 
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index de42f13145..f6f96b79c6 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -1833,16 +1833,14 @@ attribute names:
 
 ```ruby
 def full_messages
-  full_messages = []
-
-  each do |attribute, messages|
-    ...
-    attr_name = attribute.to_s.gsub('.', '_').humanize
-    attr_name = @base.class.human_attribute_name(attribute, default: attr_name)
-    ...
-  end
+  map { |attribute, message| full_message(attribute, message) }
+end
 
-  full_messages
+def full_message
+  ...
+  attr_name = attribute.to_s.tr('.', '_').humanize
+  attr_name = @base.class.human_attribute_name(attribute, default: attr_name)
+  ...
 end
 ```
 
diff --git a/guides/source/active_support_instrumentation.md b/guides/source/active_support_instrumentation.md
index 7033947468..9dfacce560 100644
--- a/guides/source/active_support_instrumentation.md
+++ b/guides/source/active_support_instrumentation.md
@@ -135,7 +135,9 @@ Action Controller
 | `:format`       | html/js/json/xml etc                                      |
 | `:method`       | HTTP request verb                                         |
 | `:path`         | Request path                                              |
+| `:status`       | HTTP status code                                          |
 | `:view_runtime` | Amount spent in view in ms                                |
+| `:db_runtime`   | Amount spent executing database queries in ms             |
 
 ```ruby
 {
@@ -223,11 +225,11 @@ Active Record
 
 ### sql.active_record
 
-| Key          | Value                 |
-| ------------ | --------------------- |
-| `:sql`       | SQL statement         |
-| `:name`      | Name of the operation |
-| `:object_id` | `self.object_id`      |
+| Key              | Value                 |
+| ---------------- | --------------------- |
+| `:sql`           | SQL statement         |
+| `:name`          | Name of the operation |
+| `:connection_id` | `self.object_id`      |
 
 INFO. The adapters will add their own data as well.
 
diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md
index c19c8e0bec..ae0f19c02a 100644
--- a/guides/source/asset_pipeline.md
+++ b/guides/source/asset_pipeline.md
@@ -1347,8 +1347,8 @@ config.assets.digest = true
 
 Rails 4 no longer sets default config values for Sprockets in `test.rb`, so
 `test.rb` now requires Sprockets configuration. The old defaults in the test
-environment are: `config.assets.compile = true`, `config.assets.compress =
-false`, `config.assets.debug = false` and `config.assets.digest = false`.
+environment are: `config.assets.compile = true`, `config.assets.compress = false`,
+`config.assets.debug = false` and `config.assets.digest = false`.
 
 The following should also be added to `Gemfile`:
 
diff --git a/guides/source/command_line.md b/guides/source/command_line.md
index b9014724bd..e72bc81766 100644
--- a/guides/source/command_line.md
+++ b/guides/source/command_line.md
@@ -61,7 +61,7 @@ With no further work, `rails server` will run our new shiny Rails app:
 $ cd commandsapp
 $ bin/rails server
 => Booting WEBrick
-=> Rails 4.2.0 application starting in development on http://0.0.0.0:3000
+=> Rails 4.2.0 application starting in development on http://localhost:3000
 => Call with -d to detach
 => Ctrl-C to shutdown server
 [2013-08-07 02:00:01] INFO  WEBrick 1.3.1
@@ -79,7 +79,7 @@ The server can be run on a different port using the `-p` option. The default dev
 $ bin/rails server -e production -p 4000
 ```
 
-The `-b` option binds Rails to the specified IP, by default it is 0.0.0.0. You can run a server as a daemon by passing a `-d` option.
+The `-b` option binds Rails to the specified IP, by default it is localhost. You can run a server as a daemon by passing a `-d` option.
 
 ### `rails generate`
 
@@ -368,8 +368,7 @@ Rake is Ruby Make, a standalone Ruby utility that replaces the Unix utility 'mak
 
 You can get a list of Rake tasks available to you, which will often depend on your current directory, by typing `rake --tasks`. Each task has a description, and should help you find the thing you need.
 
-To get the full backtrace for running rake task you can pass the option
-```--trace``` to command line, for example ```rake db:create --trace```.
+To get the full backtrace for running rake task you can pass the option ```--trace``` to command line, for example ```rake db:create --trace```.
 
 ```bash
 $ bin/rake --tasks
@@ -394,16 +393,11 @@ INFO: You can also use ```rake -T```  to get the list of tasks.
 ```bash
 $ bin/rake about
 About your application's environment
+Rails version             4.2.0
 Ruby version              1.9.3 (x86_64-linux)
 RubyGems version          1.3.6
 Rack version              1.3
-Rails version             4.2.0
 JavaScript Runtime        Node.js (V8)
-Active Record version     4.2.0
-Action Pack version       4.2.0
-Action View version       4.2.0
-Action Mailer version     4.2.0
-Active Support version    4.2.0
 Middleware                Rack::Sendfile, ActionDispatch::Static, Rack::Lock, #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x007ffd131a7c88>, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, Rails::Rack::Logger, ActionDispatch::ShowExceptions, ActionDispatch::DebugExceptions, ActionDispatch::RemoteIp, ActionDispatch::Reloader, ActionDispatch::Callbacks, ActiveRecord::Migration::CheckPending, ActiveRecord::ConnectionAdapters::ConnectionManagement, ActiveRecord::QueryCache, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, ActionDispatch::ParamsParser, Rack::Head, Rack::ConditionalGet, Rack::ETag
 Application root          /home/foobar/commandsapp
 Environment               development
@@ -413,10 +407,7 @@ Database schema version   20110805173523
 
 ### `assets`
 
-You can precompile the assets in `app/assets` using `rake assets:precompile`,
-and remove older compiled assets using `rake assets:clean`. The `assets:clean`
-task allows for rolling deploys that may still be linking to an old asset while
-the new assets are being built.
+You can precompile the assets in `app/assets` using `rake assets:precompile`, and remove older compiled assets using `rake assets:clean`. The `assets:clean` task allows for rolling deploys that may still be linking to an old asset while the new assets are being built.
 
 If you want to clear `public/assets` completely, you can use `rake assets:clobber`.
 
@@ -503,7 +494,7 @@ Rails comes with a test suite called Minitest. Rails owes its stability to the u
 
 ### `tmp`
 
-The `Rails.root/tmp` directory is, like the *nix /tmp directory, the holding place for temporary files like sessions (if you're using a file store for files), process id files, and cached actions.
+The `Rails.root/tmp` directory is, like the *nix /tmp directory, the holding place for temporary files like sessions (if you're using a file store for sessions), process id files, and cached actions.
 
 The `tmp:` namespaced tasks will help you clear and create the `Rails.root/tmp` directory:
 
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 58c3f217eb..2957232186 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -153,7 +153,7 @@ pipeline is enabled. It is set to true by default.
 
 * `config.assets.manifest` defines the full path to be used for the asset precompiler's manifest file. Defaults to a file named `manifest-<random>.json` in the `config.assets.prefix` directory within the public folder.
 
-* `config.assets.digest` enables the use of MD5 fingerprints in asset names. Set to `true` by default in `production.rb`.
+* `config.assets.digest` enables the use of MD5 fingerprints in asset names. Set to `true` by default in `production.rb` and `development.rb`.
 
 * `config.assets.debug` disables the concatenation and compression of assets. Set to `true` by default in `development.rb`.
 
diff --git a/guides/source/form_helpers.md b/guides/source/form_helpers.md
index 16fa23c129..cb45e38614 100644
--- a/guides/source/form_helpers.md
+++ b/guides/source/form_helpers.md
@@ -506,7 +506,7 @@ As the name implies, this only generates option tags. To generate a working sele
 <%= collection_select(:person, :city_id, City.all, :id, :name) %>
 ```
 
-As with other helpers, if you were to use the collection_select helper on a form builder scoped to the @person object, the syntax would be:
+As with other helpers, if you were to use the `collection_select` helper on a form builder scoped to the `@person` object, the syntax would be:
 
 ```erb
 <%= f.collection_select(:city_id, City.all, :id, :name) %>
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
index 1769448531..92f8ef5b08 100644
--- a/guides/source/getting_started.md
+++ b/guides/source/getting_started.md
@@ -195,8 +195,8 @@ TIP: Compiling CoffeeScript and JavaScript asset compression requires you
 have a JavaScript runtime available on your system, in the absence
 of a runtime you will see an `execjs` error during asset compilation.
 Usually Mac OS X and Windows come with a JavaScript runtime installed.
-Rails adds the `therubyracer` gem to the generated `Gemfile` in a 
-commented line for new apps and you can uncomment if you need it. 
+Rails adds the `therubyracer` gem to the generated `Gemfile` in a
+commented line for new apps and you can uncomment if you need it.
 `therubyrhino` is the recommended runtime for JRuby users and is added by
 default to the `Gemfile` in apps generated under JRuby. You can investigate
 all the supported runtimes at [ExecJS](https://github.com/sstephenson/execjs#readme).
@@ -338,8 +338,8 @@ You can create, read, update and destroy items for a resource and these
 operations are referred to as _CRUD_ operations.
 
 Rails provides a `resources` method which can be used to declare a standard REST
-resource. Here's what `config/routes.rb` should look like after the
-_article resource_ is declared.
+resource. You need to add the _article resource_ to the
+`config/routes.rb` as follows:
 
 ```ruby
 Rails.application.routes.draw do
diff --git a/guides/source/ruby_on_rails_guides_guidelines.md b/guides/source/ruby_on_rails_guides_guidelines.md
index 6206b3c715..c0438f6341 100644
--- a/guides/source/ruby_on_rails_guides_guidelines.md
+++ b/guides/source/ruby_on_rails_guides_guidelines.md
@@ -54,6 +54,7 @@ API Documentation Guidelines
 The guides and the API should be coherent and consistent where appropriate. In particular, these sections of the [API Documentation Guidelines](api_documentation_guidelines.html) also apply to the guides:
 
 * [Wording](api_documentation_guidelines.html#wording)
+* [English](api_documentation_guidelines.html#english)
 * [Example Code](api_documentation_guidelines.html#example-code)
 * [Filenames](api_documentation_guidelines.html#file-names)
 * [Fonts](api_documentation_guidelines.html#fonts)
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 4f10245612..ce815156a7 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -728,7 +728,7 @@ class UserFlowsTest < ActionDispatch::IntegrationTest
     https!(false)
     get "/articles/all"
     assert_response :success
-    assert assigns(:products)
+    assert assigns(:articles)
   end
 end
 ```
@@ -904,8 +904,10 @@ Testing Routes
 Like everything else in your Rails application, it is recommended that you test your routes. An example test for a route in the default `show` action of `Articles` controller above should look like:
 
 ```ruby
-test "should route to article" do
-  assert_routing '/articles/1', {controller: "articles", action: "show", id: "1"}
+class ArticleRoutesTest < ActionController::TestCase
+  test "should route to article" do
+    assert_routing '/articles/1', { controller: "articles", action: "show", id: "1" }
+  end
 end
 ```
 
@@ -1042,6 +1044,68 @@ end
 Moreover, since the test class extends from `ActionView::TestCase`, you have
 access to Rails' helper methods such as `link_to` or `pluralize`.
 
+Testing Jobs
+------------
+
+Since your custom jobs can be queued at different levels inside your application,
+you'll need to test both jobs themselves (their behavior when they get enqueued)
+and that other entities correctly enqueue them.
+
+### A Basic Test Case
+
+By default, when you generate a job, an associated test will be generated as well
+under the `test/jobs` directory. Here's an example test with a billing job:
+
+```ruby
+require 'test_helper'
+
+class BillingJobTest < ActiveJob::TestCase
+  test 'that account is charged' do
+    BillingJob.perform_now(account, product)
+    assert account.reload.charged_for?(product)
+  end
+end
+```
+
+This test is pretty simple and only asserts that the job get the work done
+as expected.
+
+By default, `ActiveJob::TestCase` will set the queue adapter to `:test` so that
+your jobs are performed inline. It will also ensure that all previously performed
+and enqueued jobs are cleared before any test run so you can safely assume that
+no jobs have already been executed in the scope of each test.
+
+### Custom Assertions And Testing Jobs Inside Other Components
+
+Active Job ships with a bunch of custom assertions that can be used to lessen
+the verbosity of tests:
+
+| Assertion                              | Purpose |
+| -------------------------------------- | ------- |
+| `assert_enqueued_jobs(number)`         | Asserts that the number of enqueued jobs matches the given number. |
+| `assert_performed_jobs(number)`        | Asserts that the number of performed jobs matches the given number. |
+| `assert_no_enqueued_jobs { ... }`      | Asserts that no jobs have been enqueued. |
+| `assert_no_performed_jobs { ... }`     | Asserts that no jobs have been performed. |
+| `assert_enqueued_with([args]) { ... }` | Asserts that the job passed in the block has been enqueued with the given arguments. |
+| `assert_performed_with([args]) { ... }`| Asserts that the job passed in the block has been performed with the given arguments. |
+
+It's a good practice to ensure that your jobs correctly get enqueued or performed
+wherever you invoke them (e.g. inside your controllers). This is precisely where
+the custom assertions provided by Active Job are pretty useful. For instance,
+within a model:
+
+```ruby
+require 'test_helper'
+
+class ProductTest < ActiveSupport::TestCase
+  test 'billing job scheduling' do
+    assert_enqueued_with(job: BillingJob) do
+      product.charge(account)
+    end
+  end
+end
+```
+
 Other Testing Approaches
 ------------------------
 
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 8a1d7af923..6f5dea45b5 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -177,11 +177,11 @@ after_bundle do
 end
 ```
 
-### Rails Html Sanitizer
+### Rails HTML Sanitizer
 
 There's a new choice for sanitizing HTML fragments in your applications. The
 venerable html-scanner approach is now officially being deprecated in favor of
-[`Rails Html Sanitizer`](https://github.com/rails/rails-html-sanitizer).
+[`Rails HTML Sanitizer`](https://github.com/rails/rails-html-sanitizer).
 
 This means the methods `sanitize`, `sanitize_css`, `strip_tags` and
 `strip_links` are backed by a new implementation.
@@ -200,15 +200,18 @@ Read the [gem's readme](https://github.com/rails/rails-html-sanitizer) for more
 The documentation for `PermitScrubber` and `TargetScrubber` explains how you
 can gain complete control over when and how elements should be stripped.
 
-If your application needs to use the old behaviour, include `rails-deprecated_sanitizer` in your Gemfile:
+If your application needs to use the old sanitizer implementation, include `rails-deprecated_sanitizer` in your Gemfile:
 
 ```ruby
 gem 'rails-deprecated_sanitizer'
 ```
 
 ### Rails DOM Testing
+The [`TagAssertions` module](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/TagAssertions.html) (containing methods such as `assert_tag`), [has been deprecated](https://github.com/rails/rails/blob/6061472b8c310158a2a2e8e9a6b81a1aef6b60fe/actionpack/lib/action_dispatch/testing/assertions/dom.rb) in favor of the `assert_select` methods from the `SelectorAssertions` module, which has been extracted into the [rails-dom-testing gem](https://github.com/rails/rails-dom-testing).
 
-TODO: Mention https://github.com/rails/rails/commit/4e97d7585a2f4788b9eed98c6cdaf4bb6f2cf5ce
+
+### Masked Authenticity Tokens
+In order to mitigate SSL attacks, `form_authenticity_token` is now masked so that it varies with each request.  Thus, tokens are validated by unmasking and then decrypting.  As a result, any strategies for verifying requests from non-rails forms that relied on a static session CSRF token have to take this into account.
 
 Upgrading from Rails 4.0 to Rails 4.1
 -------------------------------------
@@ -233,7 +236,7 @@ will now trigger CSRF protection. Switch to
 xhr :get, :index, format: :js
 ```
 
-to explicitly test an XmlHttpRequest.
+to explicitly test an `XmlHttpRequest`.
 
 If you really mean to load JavaScript from remote `<script>` tags, skip CSRF
 protection on that action.
@@ -418,7 +421,7 @@ class ReadOnlyModel < ActiveRecord::Base
 end
 ```
 
-This behaviour was never intentionally supported. Due to a change in the internals
+This behavior was never intentionally supported. Due to a change in the internals
 of `ActiveSupport::Callbacks`, this is no longer allowed in Rails 4.1. Using a
 `return` statement in an inline callback block causes a `LocalJumpError` to
 be raised when the callback is executed.
@@ -588,7 +591,7 @@ response body, you should be using `render :plain` as most browsers will escape
 unsafe content in the response for you.
 
 We will be deprecating the use of `render :text` in a future version. So please
-start using the more precise `:plain:`, `:html`, and `:body` options instead.
+start using the more precise `:plain`, `:html`, and `:body` options instead.
 Using `render :text` may pose a security risk, as the content is sent as
 `text/html`.
 
@@ -767,7 +770,7 @@ this gem such as `whitelist_attributes` or `mass_assignment_sanitizer` options.
 * Rails 4.0 has deprecated `ActiveRecord::TestCase` in favor of `ActiveSupport::TestCase`.
 
 * Rails 4.0 has deprecated the old-style hash based finder API. This means that
-  methods which previously accepted "finder options" no longer do.
+  methods which previously accepted "finder options" no longer do.  For example, `Book.find(:all, conditions: { name: '1984' })` has been deprecated in favor of `Book.where(name: '1984')`
 
 * All dynamic methods except for `find_by_...` and `find_by_...!` are deprecated.
   Here's how you can handle the changes:
@@ -792,7 +795,7 @@ Rails 4.0 extracted Active Resource to its own gem. If you still need the featur
 
 * Rails 4.0 has changed how errors attach with the `ActiveModel::Validations::ConfirmationValidator`. Now when confirmation validations fail, the error will be attached to `:#{attribute}_confirmation` instead of `attribute`.
 
-* Rails 4.0 has changed `ActiveModel::Serializers::JSON.include_root_in_json` default value to `false`. Now, Active Model Serializers and Active Record objects have the same default behaviour. This means that you can comment or remove the following option in the `config/initializers/wrap_parameters.rb` file:
+* Rails 4.0 has changed `ActiveModel::Serializers::JSON.include_root_in_json` default value to `false`. Now, Active Model Serializers and Active Record objects have the same default behavior. This means that you can comment or remove the following option in the `config/initializers/wrap_parameters.rb` file:
 
 ```ruby
 # Disable root element in JSON by default.
@@ -918,7 +921,7 @@ The order in which helpers from more than one directory are loaded has changed i
 
 ### Active Record Observer and Action Controller Sweeper
 
-Active Record Observer and Action Controller Sweeper have been extracted to the `rails-observers` gem. You will need to add the `rails-observers` gem if you require these features.
+`ActiveRecord::Observer` and `ActionController::Caching::Sweeper` have been extracted to the `rails-observers` gem. You will need to add the `rails-observers` gem if you require these features.
 
 ### sprockets-rails