Merge branch 'master' into activestorage-guide

14 files changed, 45 insertions, 42 deletions

diff --git a/guides/source/3_2_release_notes.md b/guides/source/3_2_release_notes.md
index f6571544f9..ae6eb27f35 100644
--- a/guides/source/3_2_release_notes.md
+++ b/guides/source/3_2_release_notes.md
@@ -36,7 +36,7 @@ TIP: Note that Ruby 1.8.7 p248 and p249 have marshalling bugs that crash Rails.
     * `coffee-rails ~> 3.2.1`
     * `uglifier >= 1.0.3`
 
-* Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
+* Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your `Gemfile`. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
 
 * There are a couple of new configuration changes you'd want to add in `config/environments/development.rb`:
 
@@ -156,7 +156,7 @@ Railties
 
     will create indexes for `title` and `author` with the latter being a unique index. Some types such as decimal accept custom options. In the example, `price` will be a decimal column with precision and scale set to 7 and 2 respectively.
 
-* Turn gem has been removed from default Gemfile.
+* Turn gem has been removed from default `Gemfile`.
 
 * Remove old plugin generator `rails generate plugin` in favor of `rails plugin new` command.
 
diff --git a/guides/source/4_1_release_notes.md b/guides/source/4_1_release_notes.md
index 6bf65757ec..2c5e665e33 100644
--- a/guides/source/4_1_release_notes.md
+++ b/guides/source/4_1_release_notes.md
@@ -274,7 +274,7 @@ for detailed changes.
 * The [Spring application
   preloader](https://github.com/rails/spring) is now installed
   by default for new applications. It uses the development group of
-  the Gemfile, so will not be installed in
+  the `Gemfile`, so will not be installed in
   production. ([Pull Request](https://github.com/rails/rails/pull/12958))
 
 * `BACKTRACE` environment variable to show unfiltered backtraces for test
diff --git a/guides/source/4_2_release_notes.md b/guides/source/4_2_release_notes.md
index 036a310ac8..7105df5634 100644
--- a/guides/source/4_2_release_notes.md
+++ b/guides/source/4_2_release_notes.md
@@ -368,7 +368,7 @@ Please refer to the [Changelog][railties] for detailed changes.
 
 ### Notable changes
 
-*   Introduced `web-console` in the default application Gemfile.
+*   Introduced `web-console` in the default application `Gemfile`.
     ([Pull Request](https://github.com/rails/rails/pull/11667))
 
 *   Added a `required` option to the model generator for associations.
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
index c1e02745de..fde2040173 100644
--- a/guides/source/action_view_overview.md
+++ b/guides/source/action_view_overview.md
@@ -149,10 +149,10 @@ end
 
 #### Jbuilder
 [Jbuilder](https://github.com/rails/jbuilder) is a gem that's
-maintained by the Rails team and included in the default Rails Gemfile.
+maintained by the Rails team and included in the default Rails `Gemfile`.
 It's similar to Builder, but is used to generate JSON, instead of XML.
 
-If you don't have it, you can add the following to your Gemfile:
+If you don't have it, you can add the following to your `Gemfile`:
 
 ```ruby
 gem 'jbuilder'
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index 3786343fc3..4e28e31a53 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -801,7 +801,7 @@ The SQL that would be executed:
 SELECT * FROM articles WHERE id > 10 ORDER BY id DESC
 
 # Original query without `only`
-SELECT "articles".* FROM "articles" WHERE (id > 10) ORDER BY id desc LIMIT 20
+SELECT * FROM articles WHERE id > 10 ORDER BY id DESC LIMIT 20
 
 ```
 
@@ -820,14 +820,14 @@ Article.find(10).comments.reorder('name')
 The SQL that would be executed:
 
 ```sql
-SELECT * FROM articles WHERE id = 10
+SELECT * FROM articles WHERE id = 10 LIMIT 1
 SELECT * FROM comments WHERE article_id = 10 ORDER BY name
 ```
 
 In the case where the `reorder` clause is not used, the SQL executed would be:
 
 ```sql
-SELECT * FROM articles WHERE id = 10
+SELECT * FROM articles WHERE id = 10 LIMIT 1
 SELECT * FROM comments WHERE article_id = 10 ORDER BY posted_at DESC
 ```
 
@@ -1091,7 +1091,7 @@ This produces:
 
 ```sql
 SELECT articles.* FROM articles
-  INNER JOIN categories ON articles.category_id = categories.id
+  INNER JOIN categories ON categories.id = articles.category_id
   INNER JOIN comments ON comments.article_id = articles.id
 ```
 
@@ -1871,14 +1871,14 @@ All calculation methods work directly on a model:
 
 ```ruby
 Client.count
-# SELECT count(*) AS count_all FROM clients
+# SELECT COUNT(*) FROM clients
 ```
 
 Or on a relation:
 
 ```ruby
 Client.where(first_name: 'Ryan').count
-# SELECT count(*) AS count_all FROM clients WHERE (first_name = 'Ryan')
+# SELECT COUNT(*) FROM clients WHERE (first_name = 'Ryan')
 ```
 
 You can also use various finder methods on a relation for performing complex calculations:
@@ -1890,9 +1890,9 @@ Client.includes("orders").where(first_name: 'Ryan', orders: { status: 'received'
 Which will execute:
 
 ```sql
-SELECT count(DISTINCT clients.id) AS count_all FROM clients
-  LEFT OUTER JOIN orders ON orders.client_id = clients.id WHERE
-  (clients.first_name = 'Ryan' AND orders.status = 'received')
+SELECT COUNT(DISTINCT clients.id) FROM clients
+  LEFT OUTER JOIN orders ON orders.client_id = clients.id
+  WHERE (clients.first_name = 'Ryan' AND orders.status = 'received')
 ```
 
 ### Count
diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md
index 805b0f0d62..e6d5aed135 100644
--- a/guides/source/asset_pipeline.md
+++ b/guides/source/asset_pipeline.md
@@ -35,7 +35,7 @@ rails new appname --skip-sprockets
 ```
 
 Rails automatically adds the `sass-rails`, `coffee-rails` and `uglifier`
-gems to your Gemfile, which are used by Sprockets for asset compression:
+gems to your `Gemfile`, which are used by Sprockets for asset compression:
 
 ```ruby
 gem 'sass-rails'
@@ -44,8 +44,8 @@ gem 'coffee-rails'
 ```
 
 Using the `--skip-sprockets` option will prevent Rails from adding
-them to your Gemfile, so if you later want to enable
-the asset pipeline you will have to add those gems to your Gemfile. Also,
+them to your `Gemfile`, so if you later want to enable
+the asset pipeline you will have to add those gems to your `Gemfile`. Also,
 creating an application with the `--skip-sprockets` option will generate
 a slightly different `config/application.rb` file, with a require statement
 for the sprockets railtie that is commented-out. You will have to remove
@@ -850,7 +850,7 @@ This mode uses more memory, performs more poorly than the default and is not
 recommended.
 
 If you are deploying a production application to a system without any
-pre-existing JavaScript runtimes, you may want to add one to your Gemfile:
+pre-existing JavaScript runtimes, you may want to add one to your `Gemfile`:
 
 ```ruby
 group :production do
diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md
index 31bc478015..780e69c146 100644
--- a/guides/source/caching_with_rails.md
+++ b/guides/source/caching_with_rails.md
@@ -32,7 +32,7 @@ Basic Caching
 This is an introduction to three types of caching techniques: page, action and
 fragment caching. By default Rails provides fragment caching. In order to use
 page and action caching you will need to add `actionpack-page_caching` and
-`actionpack-action_caching` to your Gemfile.
+`actionpack-action_caching` to your `Gemfile`.
 
 By default, caching is only enabled in your production environment. To play
 around with caching locally you'll want to enable caching in your local
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 4bfcc1e21a..fee644d4d4 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -1005,11 +1005,11 @@ Deploying your application using a reverse proxy has definite advantages over tr
 
 Many modern web servers can be used as a proxy server to balance third-party elements such as caching servers or application servers.
 
-One such application server you can use is [Unicorn](http://unicorn.bogomips.org/) to run behind a reverse proxy.
+One such application server you can use is [Unicorn](https://bogomips.org/unicorn/) to run behind a reverse proxy.
 
 In this case, you would need to configure the proxy server (NGINX, Apache, etc) to accept connections from your application server (Unicorn). By default Unicorn will listen for TCP connections on port 8080, but you can change the port or configure it to use sockets instead.
 
-You can find more information in the [Unicorn readme](http://unicorn.bogomips.org/README.html) and understand the [philosophy](http://unicorn.bogomips.org/PHILOSOPHY.html) behind it.
+You can find more information in the [Unicorn readme](https://bogomips.org/unicorn/README.html) and understand the [philosophy](https://bogomips.org/unicorn/PHILOSOPHY.html) behind it.
 
 Once you've configured the application server, you must proxy requests to it by configuring your web server appropriately. For example your NGINX config may include:
 
@@ -1037,7 +1037,7 @@ server {
 }
 ```
 
-Be sure to read the [NGINX documentation](http://nginx.org/en/docs/) for the most up-to-date information.
+Be sure to read the [NGINX documentation](https://nginx.org/en/docs/) for the most up-to-date information.
 
 
 Rails Environment Settings
diff --git a/guides/source/form_helpers.md b/guides/source/form_helpers.md
index 4ce67df93a..f8ec389b01 100644
--- a/guides/source/form_helpers.md
+++ b/guides/source/form_helpers.md
@@ -920,7 +920,7 @@ When an association accepts nested attributes `fields_for` renders its block onc
 ```ruby
 def new
   @person = Person.new
-  2.times { @person.addresses.build}
+  2.times { @person.addresses.build }
 end
 ```
 
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
index e6aa6181cc..2b545e6b82 100644
--- a/guides/source/i18n.md
+++ b/guides/source/i18n.md
@@ -977,7 +977,7 @@ en:
 ```
 
 NOTE: In order to use this helper, you need to install [DynamicForm](https://github.com/joelmoss/dynamic_form)
-gem by adding this line to your Gemfile: `gem 'dynamic_form'`.
+gem by adding this line to your `Gemfile`: `gem 'dynamic_form'`.
 
 ### Translations for Action Mailer E-Mail Subjects
 
diff --git a/guides/source/initialization.md b/guides/source/initialization.md
index 1541ea38cd..c4f1df487b 100644
--- a/guides/source/initialization.md
+++ b/guides/source/initialization.md
@@ -93,7 +93,7 @@ require 'bundler/setup' # Set up gems listed in the Gemfile.
 
 In a standard Rails application, there's a `Gemfile` which declares all
 dependencies of the application. `config/boot.rb` sets
-`ENV['BUNDLE_GEMFILE']` to the location of this file. If the Gemfile
+`ENV['BUNDLE_GEMFILE']` to the location of this file. If the `Gemfile`
 exists, then `bundler/setup` is required. The require is used by Bundler to
 configure the load path for your Gemfile's dependencies.
 
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 8416fd163d..f28c4c224a 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -319,6 +319,8 @@ specify to make your test failure messages clearer.
 | `assert_not_includes( collection, obj, [msg] )`                  | Ensures that `obj` is not in `collection`.|
 | `assert_in_delta( expected, actual, [delta], [msg] )`            | Ensures that the numbers `expected` and `actual` are within `delta` of each other.|
 | `assert_not_in_delta( expected, actual, [delta], [msg] )`        | Ensures that the numbers `expected` and `actual` are not within `delta` of each other.|
+| `assert_in_epsilon ( expected, actual, [epsilon], [msg] )`       | Ensures that the numbers `expected` and `actual` have a relative error less than `epsilon`.|
+| `assert_not_in_epsilon ( expected, actual, [epsilon], [msg] )`   | Ensures that the numbers `expected` and `actual` don't have a relative error less than `epsilon`.|
 | `assert_throws( symbol, [msg] ) { block }`                       | Ensures that the given block throws the symbol.|
 | `assert_raises( exception1, exception2, ... ) { block }`         | Ensures that the given block raises one of the given exceptions.|
 | `assert_instance_of( class, obj, [msg] )`                        | Ensures that `obj` is an instance of `class`.|
@@ -645,7 +647,7 @@ system tests should live.
 
 If you want to change the default settings you can change what the system
 tests are "driven by". Say you want to change the driver from Selenium to
-Poltergeist. First add the `poltergeist` gem to your Gemfile. Then in your
+Poltergeist. First add the `poltergeist` gem to your `Gemfile`. Then in your
 `application_system_test_case.rb` file do the following:
 
 ```ruby
@@ -671,7 +673,8 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
 end
 ```
 
-If you want to use a headless browser, you could use Headless Chrome by adding `headless_chrome` in the `:using` argument.
+If you want to use a headless browser, you could use Headless Chrome or Headless Firefox by adding
+`headless_chrome` or `headless_firefox` in the `:using` argument.
 
 ```ruby
 require "test_helper"
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 9bc87e4bf0..eae73c3e1b 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -45,7 +45,7 @@ TIP: Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterp
 ### The Update Task
 
 Rails provides the `app:update` task (`rake rails:update` on 4.2 and earlier). After updating the Rails version
-in the Gemfile, run this task.
+in the `Gemfile`, run this task.
 This will help you with the creation of new files and changes of old files in an
 interactive session.
 
@@ -179,7 +179,7 @@ See [#19034](https://github.com/rails/rails/pull/19034) for more details.
 
 `assigns` and `assert_template` have been extracted to the `rails-controller-testing` gem. To
 continue using these methods in your controller tests, add `gem 'rails-controller-testing'` to
-your Gemfile.
+your `Gemfile`.
 
 If you are using Rspec for testing, please see the extra configuration required in the gem's
 documentation.
@@ -212,7 +212,7 @@ true.
 
 `ActiveModel::Serializers::Xml` has been extracted from Rails to the `activemodel-serializers-xml`
 gem. To continue using XML serialization in your application, add `gem 'activemodel-serializers-xml'`
-to your Gemfile.
+to your `Gemfile`.
 
 ### Removed Support for Legacy `mysql` Database Adapter
 
@@ -278,7 +278,7 @@ You can now just call the dependency once with a wildcard.
 
 ### `ActionView::Helpers::RecordTagHelper` moved to external gem (record_tag_helper)
 
-`content_tag_for` and `div_for` have been removed in favor of just using `content_tag`. To continue using the older methods, add the `record_tag_helper` gem to your Gemfile:
+`content_tag_for` and `div_for` have been removed in favor of just using `content_tag`. To continue using the older methods, add the `record_tag_helper` gem to your `Gemfile`:
 
 ```ruby
 gem 'record_tag_helper', '~> 1.0'
@@ -415,7 +415,7 @@ First, add `gem 'web-console', '~> 2.0'` to the `:development` group in your `Ge
 
 ### Responders
 
-`respond_with` and the class-level `respond_to` methods have been extracted to the `responders` gem. To use them, simply add `gem 'responders', '~> 2.0'` to your Gemfile. Calls to `respond_with` and `respond_to` (again, at the class level) will no longer work without having included the `responders` gem in your dependencies:
+`respond_with` and the class-level `respond_to` methods have been extracted to the `responders` gem. To use them, simply add `gem 'responders', '~> 2.0'` to your `Gemfile`. Calls to `respond_with` and `respond_to` (again, at the class level) will no longer work without having included the `responders` gem in your dependencies:
 
 ```ruby
 # app/controllers/users_controller.rb
@@ -559,7 +559,7 @@ 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 sanitizer implementation, 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'
@@ -617,7 +617,7 @@ migration DSL counterpart.
 
 The migration procedure is as follows:
 
-1. remove `gem "foreigner"` from the Gemfile.
+1. remove `gem "foreigner"` from the `Gemfile`.
 2. run `bundle install`.
 3. run `bin/rake db:schema:dump`.
 4. make sure that `db/schema.rb` contains every foreign key definition with
@@ -769,7 +769,7 @@ and has been removed from Rails.
 
 If your application currently depends on MultiJSON directly, you have a few options:
 
-1. Add 'multi_json' to your Gemfile. Note that this might cease to work in the future
+1. Add 'multi_json' to your `Gemfile`. Note that this might cease to work in the future
 
 2. Migrate away from MultiJSON by using `obj.to_json`, and `JSON.parse(str)` instead.
 
@@ -810,7 +810,7 @@ part of the rewrite, the following features have been removed from the encoder:
 
 If your application depends on one of these features, you can get them back by
 adding the [`activesupport-json_encoder`](https://github.com/rails/activesupport-json_encoder)
-gem to your Gemfile.
+gem to your `Gemfile`.
 
 #### JSON representation of Time objects
 
@@ -1135,7 +1135,7 @@ full support for the last few changes in the specification.
 
 ### Gemfile
 
-Rails 4.0 removed the `assets` group from Gemfile. You'd need to remove that
+Rails 4.0 removed the `assets` group from `Gemfile`. You'd need to remove that
 line from your `Gemfile` when upgrading. You should also update your application
 file (in `config/application.rb`):
 
@@ -1147,7 +1147,7 @@ Bundler.require(*Rails.groups)
 
 ### vendor/plugins
 
-Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must replace any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
+Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must replace any plugins by extracting them to gems and adding them to your `Gemfile`. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
 
 ### Active Record
 
@@ -1214,7 +1214,7 @@ end
 
 ### Active Resource
 
-Rails 4.0 extracted Active Resource to its own gem. If you still need the feature you can add the [Active Resource gem](https://github.com/rails/activeresource) in your Gemfile.
+Rails 4.0 extracted Active Resource to its own gem. If you still need the feature you can add the [Active Resource gem](https://github.com/rails/activeresource) in your `Gemfile`.
 
 ### Active Model
 
@@ -1414,7 +1414,7 @@ config.active_record.mass_assignment_sanitizer = :strict
 
 ### vendor/plugins
 
-Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
+Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your `Gemfile`. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`.
 
 ### Active Record
 
diff --git a/guides/source/working_with_javascript_in_rails.md b/guides/source/working_with_javascript_in_rails.md
index 86746a5ae0..c3dff1772c 100644
--- a/guides/source/working_with_javascript_in_rails.md
+++ b/guides/source/working_with_javascript_in_rails.md
@@ -492,7 +492,7 @@ replace the entire `<body>` of the page with the `<body>` of the response. It
 will then use PushState to change the URL to the correct one, preserving
 refresh semantics and giving you pretty URLs.
 
-The only thing you have to do to enable Turbolinks is have it in your Gemfile,
+The only thing you have to do to enable Turbolinks is have it in your `Gemfile`,
 and put `//= require turbolinks` in your JavaScript manifest, which is usually
 `app/assets/javascripts/application.js`.