8 files changed, 32 insertions, 33 deletions
diff --git a/guides/source/5_0_release_notes.md b/guides/source/5_0_release_notes.md
index 4e8252f85b..f5abbd0cd4 100644
--- a/guides/source/5_0_release_notes.md
+++ b/guides/source/5_0_release_notes.md
@@ -294,6 +294,9 @@ Please refer to the [Changelog][action-view] for detailed changes.
     button on submit to prevent double submits.
     ([Pull Request](https://github.com/rails/rails/pull/21135))
 
+*   Downcase model name in form submit tags rather than humanize.
+    ([Pull Request](https://github.com/rails/rails/pull/22764))
+
 
 Action Mailer
 -------------
@@ -705,7 +708,7 @@ Please refer to the [Changelog][active-support] for detailed changes.
 *   Changed the default test order from `:sorted` to `:random`.
     ([commit](https://github.com/rails/rails/commit/5f777e4b5ee2e3e8e6fd0e2a208ec2a4d25a960d))
 
-*   Added `#on_weekend?`, `#next_weekday`, `#prev_weekday` methods to `Date`,
+*   Added `#on_weekend?`, `#on_weekday?`, `#next_weekday`, `#prev_weekday` methods to `Date`,
     `Time`, and `DateTime`.
     ([Pull Request](https://github.com/rails/rails/pull/18335))
 
@@ -768,6 +771,7 @@ framework it is. Kudos to all of them.
 [action-pack]:    https://github.com/rails/rails/blob/5-0-stable/actionpack/CHANGELOG.md
 [action-view]:    https://github.com/rails/rails/blob/5-0-stable/actionview/CHANGELOG.md
 [action-mailer]:  https://github.com/rails/rails/blob/5-0-stable/actionmailer/CHANGELOG.md
+[action-cable]:   https://github.com/rails/rails/blob/5-0-stable/actioncable/CHANGELOG.md
 [active-record]:  https://github.com/rails/rails/blob/5-0-stable/activerecord/CHANGELOG.md
 [active-model]:   https://github.com/rails/rails/blob/5-0-stable/activemodel/CHANGELOG.md
 [active-support]: https://github.com/rails/rails/blob/5-0-stable/activesupport/CHANGELOG.md
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index 1235c04c50..af15d4870c 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -11,7 +11,7 @@ After reading this guide, you will know:
 * How to specify the order, retrieved attributes, grouping, and other properties of the found records.
 * How to use eager loading to reduce the number of database queries needed for data retrieval.
 * How to use dynamic finder methods.
-* How to use method chaining to use multiple ActiveRecord methods together.
+* How to use method chaining to use multiple Active Record methods together.
 * How to check for the existence of particular records.
 * How to perform various calculations on Active Record models.
 * How to run EXPLAIN on relations.
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
index dd7adf09a2..10bd201145 100644
--- a/guides/source/active_record_validations.md
+++ b/guides/source/active_record_validations.md
@@ -149,7 +149,7 @@ false` as an argument. This technique should be used with caution.
 
 ### `valid?` and `invalid?`
 
-Before saving an ActiveRecord object, Rails runs your validations.
+Before saving an Active Record object, Rails runs your validations.
 If these validations produce any errors, Rails does not save the object.
 
 You can also run these validations on your own. `valid?` triggers your validations
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index 10122629b2..e66b9a4301 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -3078,7 +3078,7 @@ INFO: The following calculation methods have edge cases in October 1582, since d
 
 #### `Date.current`
 
-Active Support defines `Date.current` to be today in the current time zone. That's like `Date.today`, except that it honors the user time zone, if defined. It also defines `Date.yesterday` and `Date.tomorrow`, and the instance predicates `past?`, `today?`, and `future?`, all of them relative to `Date.current`.
+Active Support defines `Date.current` to be today in the current time zone. That's like `Date.today`, except that it honors the user time zone, if defined. It also defines `Date.yesterday` and `Date.tomorrow`, and the instance predicates `past?`, `today?`, `future?`, `on_weekday?` and `on_weekend?`, all of them relative to `Date.current`.
 
 When making Date comparisons using methods which honor the user time zone, make sure to use `Date.current` and not `Date.today`. There are cases where the user time zone might be in the future compared to the system time zone, which `Date.today` uses by default. This means `Date.today` may equal `Date.yesterday`.
 
@@ -3467,6 +3467,8 @@ years_ago
 years_since
 prev_year (last_year)
 next_year
+on_weekday?
+on_weekend?
 ```
 
 The following methods are reimplemented so you do **not** need to load `active_support/core_ext/date/calculations.rb` for these ones:
@@ -3653,6 +3655,8 @@ years_ago
 years_since
 prev_year (last_year)
 next_year
+on_weekday?
+on_weekend?
 ```
 
 They are analogous. Please refer to their documentation above and take into account the following differences:
diff --git a/guides/source/api_app.md b/guides/source/api_app.md
index 563214896a..0598b9c7fa 100644
--- a/guides/source/api_app.md
+++ b/guides/source/api_app.md
@@ -13,8 +13,8 @@ In this guide you will learn:
 
 --------------------------------------------------------------------------------
 
-What is an API app?
--------------------
+What is an API Application?
+---------------------------
 
 Traditionally, when people said that they used Rails as an "API", they meant
 providing a programmatically accessible API alongside their web application.
@@ -28,15 +28,14 @@ applications.
 For example, Twitter uses its [public API](https://dev.twitter.com) in its web
 application, which is built as a static site that consumes JSON resources.
 
-Instead of using Rails to generate dynamic HTML that will communicate with the
-server through forms and links, many developers are treating their web application
-as just another client, delivered as static HTML, CSS and JavaScript  consuming
-a simple JSON API.
+Instead of using Rails to generate HTML that communicates with the server
+through forms and links, many developers are treating their web application as
+just an API client delivered as HTML with JavaScript that consumes a JSON API.
 
 This guide covers building a Rails application that serves JSON resources to an
-API client **or** a client-side framework.
+API client, including client-side frameworks.
 
-Why use Rails for JSON APIs?
+Why Use Rails for JSON APIs?
 ----------------------------
 
 The first question a lot of people have when thinking about building a JSON API
@@ -75,7 +74,7 @@ Handled at the middleware layer:
   URL-encoded String? No problem. Rails will decode the JSON for you and make
   it available in `params`. Want to use nested URL-encoded parameters? That
   works too.
-- Conditional GETs: Rails handles conditional `GET`, (`ETag` and `Last-Modified`),
+- Conditional GETs: Rails handles conditional `GET` (`ETag` and `Last-Modified`)
   processing request headers and returning the correct response headers and status
   code. All you need to do is use the
   [`stale?`](http://api.rubyonrails.org/classes/ActionController/ConditionalGet.html#method-i-stale-3F)
@@ -104,21 +103,21 @@ Handled at the Action Pack layer:
   add the response headers, but why?
 - Caching: Rails provides page, action and fragment caching. Fragment caching
   is especially helpful when building up a nested JSON object.
-- Basic, Digest and Token Authentication: Rails comes with out-of-the-box support
+- Basic, Digest, and Token Authentication: Rails comes with out-of-the-box support
   for three kinds of HTTP authentication.
-- Instrumentation: Rails has an instrumentation API that will trigger registered
+- Instrumentation: Rails has an instrumentation API that triggers registered
   handlers for a variety of events, such as action processing, sending a file or
   data, redirection, and database queries. The payload of each event comes with
   relevant information (for the action processing event, the payload includes
   the controller, action, parameters, request format, request method and the
   request's full path).
-- Generators: This may be passé for advanced Rails users, but it can be nice to
-  generate a resource and get your model, controller, test stubs, and routes
-  created for you in a single command.
+- Generators: It is often handy to generate a resource and get your model,
+  controller, test stubs, and routes created for you in a single command for
+  further tweaking. Same for migrations and others.
 - Plugins: Many third-party libraries come with support for Rails that reduce
   or eliminate the cost of setting up and gluing together the library and the
   web framework. This includes things like overriding default generators, adding
-  rake tasks, and honoring Rails choices (like the logger and cache back-end).
+  Rake tasks, and honoring Rails choices (like the logger and cache back-end).
 
 Of course, the Rails boot process also glues together all registered components.
 For example, the Rails boot process is what uses your `config/database.yml` file
@@ -167,14 +166,6 @@ class definition:
 config.api_only = true
 ```
 
-Optionally, in `config/environments/development.rb` add the following line
-to render error responses using the API format (JSON by default) when it
-is a local request:
-
-```ruby
-config.debug_exception_response_format = :api
-```
-
 Finally, inside `app/controllers/application_controller.rb`, instead of:
 
 ```ruby
diff --git a/guides/source/engines.md b/guides/source/engines.md
index db50ad278f..c5fc2f73b4 100644
--- a/guides/source/engines.md
+++ b/guides/source/engines.md
@@ -402,8 +402,8 @@ module Blorgh
 end
 ```
 
-NOTE: The `ApplicationController` class being inherited from here is the
-`Blorgh::ApplicationController`, not an application's `ApplicationController`.
+NOTE: The `ArticlesController` class inherits from
+`Blorgh::ApplicationController`, not the application's `ApplicationController`.
 
 The helper inside `app/helpers/blorgh/articles_helper.rb` is also namespaced:
 
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
index 5bbd4048b9..56b0c6c812 100644
--- a/guides/source/i18n.md
+++ b/guides/source/i18n.md
@@ -25,7 +25,7 @@ After reading this guide, you will know:
 
 * How I18n works in Ruby on Rails
 * How to correctly use I18n into a RESTful application in various ways
-* How to use I18n to translate ActiveRecord errors or ActionMailer E-mail subjects
+* How to use I18n to translate Active Record errors or Action Mailer E-mail subjects
 * Some other tools to go further with the translation process of your application
 
 --------------------------------------------------------------------------------
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 13f4446751..7a9a30f7ac 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -1191,9 +1191,9 @@ testing) but instead it will be appended to an array
 (`ActionMailer::Base.deliveries`).
 
 NOTE: The `ActionMailer::Base.deliveries` array is only reset automatically in
-`ActionMailer::TestCase` tests. If you want to have a clean slate outside Action
-Mailer tests, you can reset it manually with:
-`ActionMailer::Base.deliveries.clear`
+`ActionMailer::TestCase` and `ActionDispatch::IntegrationTest` tests.
+If you want to have a clean slate outside these test cases, you can reset it
+manually with: `ActionMailer::Base.deliveries.clear`
 
 ### Functional Testing