10 files changed, 63 insertions, 21 deletions

diff --git a/guides/source/action_mailer_basics.md b/guides/source/action_mailer_basics.md
index 6f159b2fc4..c31b50fcfc 100644
--- a/guides/source/action_mailer_basics.md
+++ b/guides/source/action_mailer_basics.md
@@ -533,6 +533,24 @@ url helper.
 NOTE: non-`GET` links require [jQuery UJS](https://github.com/rails/jquery-ujs)
 and won't work in mailer templates. They will result in normal `GET` requests.
 
+### Adding images in Action Mailer Views
+
+Unlike controllers, the mailer instance doesn't have any context about the
+incoming request so you'll need to provide the `:asset_host` parameter yourself.
+
+As the `:asset_host` usually is consistent across the application you can
+configure it globally in config/application.rb:
+
+```ruby
+config.action_mailer.asset_host = 'http://example.com'
+```
+
+Now you can display an image inside your email.
+
+```ruby
+<%= image_tag 'image.jpg' %>
+```
+
 ### Sending Multipart Emails
 
 Action Mailer will automatically send multipart emails if you have different
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
index 3c1c3c7873..98c6cbd540 100644
--- a/guides/source/action_view_overview.md
+++ b/guides/source/action_view_overview.md
@@ -1059,14 +1059,6 @@ If `@article.author_ids` is [1], this would return:
 <input name="article[author_ids][]" type="hidden" value="" />
 ```
 
-#### country_options_for_select
-
-Returns a string of option tags for pretty much any country in the world.
-
-#### country_select
-
-Returns select and option tags for the given object and method, using country_options_for_select to generate the list of option tags.
-
 #### option_groups_from_collection_for_select
 
 Returns a string of `option` tags, like `options_from_collection_for_select`, but groups them by `optgroup` tags based on the object relationships of the arguments.
@@ -1153,8 +1145,8 @@ If `@article.person_id` is 1, this would become:
 <select name="article[person_id]">
   <option value=""></option>
   <option value="1" selected="selected">David</option>
-  <option value="2">Sam</option>
-  <option value="3">Tobias</option>
+  <option value="2">Eileen</option>
+  <option value="3">Rafael</option>
 </select>
 ```
 
diff --git a/guides/source/active_job_basics.md b/guides/source/active_job_basics.md
index 22f3c0146a..dd545b56f5 100644
--- a/guides/source/active_job_basics.md
+++ b/guides/source/active_job_basics.md
@@ -330,6 +330,13 @@ class GuestsCleanupJob < ActiveJob::Base
 end
 ```
 
+### Deserialization
+
+GlobalID allows serializing full Active Record objects passed to `#perform`.
+
+If a passed record is deleted after the job is enqueued but before the `#perform`
+method is called Active Job will raise an `ActiveJob::DeserializationError`
+exception.
 
 Job Testing
 --------------
diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md
index 0b84001ca5..ce605c912e 100644
--- a/guides/source/active_record_migrations.md
+++ b/guides/source/active_record_migrations.md
@@ -477,7 +477,7 @@ column names can not be derived from the table names, you can use the
 `:column` and `:primary_key` options.
 
 Rails will generate a name for every foreign key starting with
-`fk_rails_` followed by 10 character which is deterministically
+`fk_rails_` followed by 10 characters which are deterministically
 generated from the `from_table` and `column`.
 There is a `:name` option to specify a different name if needed.
 
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
index 7932853c11..71ca7a0f66 100644
--- a/guides/source/active_record_validations.md
+++ b/guides/source/active_record_validations.md
@@ -965,8 +965,9 @@ own custom validators.
 
 You can also create methods that verify the state of your models and add
 messages to the `errors` collection when they are invalid. You must then
-register these methods by using the `validate` class method, passing in the
-symbols for the validation methods' names.
+register these methods by using the `validate`
+([API](http://api.rubyonrails.org/classes/ActiveModel/Validations/ClassMethods.html#method-i-validate))
+class method, passing in the symbols for the validation methods' names.
 
 You can pass more than one symbol for each class method and the respective
 validations will be run in the same order as they were registered.
diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md
index a514f89d5f..20f11c2bc2 100644
--- a/guides/source/caching_with_rails.md
+++ b/guides/source/caching_with_rails.md
@@ -127,7 +127,7 @@ For example, take the following view:
 Which in turn renders this view:
 
 ```erb
-<% cache game %>
+<% cache game do %>
   <%= render game %>
 <% end %>
 ```
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 496000d637..167cc549e2 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -181,7 +181,7 @@ The full set of methods that can be used in this block are as follows:
 * `assets` allows to create assets on generating a scaffold. Defaults to `true`.
 * `force_plural` allows pluralized model names. Defaults to `false`.
 * `helper` defines whether or not to generate helpers. Defaults to `true`.
-* `integration_tool` defines which integration tool to use. Defaults to `nil`.
+* `integration_tool` defines which integration tool to use to generate integration tests. Defaults to `:test_unit`.
 * `javascripts` turns on the hook for JavaScript files in generators. Used in Rails for when the `scaffold` generator is run. Defaults to `true`.
 * `javascript_engine` configures the engine to be used (for eg. coffee) when generating assets. Defaults to `:js`.
 * `orm` defines which orm to use. Defaults to `false` and will use Active Record by default.
diff --git a/guides/source/contributing_to_ruby_on_rails.md b/guides/source/contributing_to_ruby_on_rails.md
index c19813c8a5..2e86eee587 100644
--- a/guides/source/contributing_to_ruby_on_rails.md
+++ b/guides/source/contributing_to_ruby_on_rails.md
@@ -61,7 +61,7 @@ can expect it to be marked "invalid" as soon as it's reviewed.
 
 Sometimes, the line between 'bug' and 'feature' is a hard one to draw.
 Generally, a feature is anything that adds new behavior, while a bug is
-anything that fixes already existing behavior that is misbehaving. Sometimes,
+anything that causes incorrect behavior. Sometimes,
 the core team will have to make a judgement call. That said, the distinction
 generally just affects which release your patch will get in to; we love feature
 submissions! They just won't get backported to maintenance branches.
@@ -295,7 +295,7 @@ You can run a single test through ruby. For instance:
 
 ```bash
 $ cd actionmailer
-$ ruby -w -Itest test/mail_layout_test.rb -n test_explicit_class_layout
+$ bundle exec ruby -w -Itest test/mail_layout_test.rb -n test_explicit_class_layout
 ```
 
 The `-n` option allows you to run a single method instead of the whole
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
index dfdc11de7a..400383cfb5 100644
--- a/guides/source/getting_started.md
+++ b/guides/source/getting_started.md
@@ -23,7 +23,8 @@ application from scratch. It does not assume that you have any prior experience
 with Rails. However, to get the most out of it, you need to have some
 prerequisites installed:
 
-* The [Ruby](https://www.ruby-lang.org/en/downloads) language version 2.2.2 or newer.
+* The [Ruby](https://www.ruby-lang.org/en/downloads) language version 2.2.2 or newer. 
+* Right version of [Development Kit](http://rubyinstaller.org/downloads/), if you are using Windows
 * The [RubyGems](https://rubygems.org) packaging system, which is installed with Ruby
   versions 1.9 and later. To learn more about RubyGems, please read the [RubyGems Guides](http://guides.rubygems.org).
 * A working installation of the [SQLite3 Database](https://www.sqlite.org).
@@ -620,7 +621,7 @@ def create
 end
 ```
 
-The `render` method here is taking a very simple hash with a key of `plain` and
+The `render` method here is taking a very simple hash with a key of `:plain` and
 value of `params[:article].inspect`. The `params` method is the object which
 represents the parameters (or fields) coming in from the form. The `params`
 method returns an `ActiveSupport::HashWithIndifferentAccess` object, which
@@ -1555,8 +1556,8 @@ end
 ```
 
 The `t.references` line creates an integer column called `article_id`, an index
-for it, and a foreign key constraint that points to the `articles` table. Go
-ahead and run the migration:
+for it, and a foreign key constraint that points to the `id` column of the `articles`
+table. Go ahead and run the migration:
 
 ```bash
 $ bin/rake db:migrate
diff --git a/guides/source/security.md b/guides/source/security.md
index 93580d4d4e..485b108d12 100644
--- a/guides/source/security.md
+++ b/guides/source/security.md
@@ -1026,6 +1026,29 @@ Environmental Security
 
 It is beyond the scope of this guide to inform you on how to secure your application code and environments. However, please secure your database configuration, e.g. `config/database.yml`, and your server-side secret, e.g. stored in `config/secrets.yml`. You may want to further restrict access, using environment-specific versions of these files and any others that may contain sensitive information.
 
+### Custom secrets
+
+Rails generates a `config/secrets.yml`. By default, this file contains the
+application's `secret_key_base`, but it could also be used to store other
+secrets such as access keys for external APIs.
+
+The secrets added to this file are accessible via `Rails.application.secrets`.
+For example, with the following `config/secrets.yml`:
+
+    development:
+      secret_key_base: 3b7cd727ee24e8444053437c36cc66c3
+      some_api_key: SOMEKEY
+
+`Rails.application.secrets.some_api_key` returns `SOMEKEY` in the development
+environment.
+
+If you want an exception to be raised when some key is blank, use the bang
+version:
+
+```ruby
+Rails.application.secrets.some_api_key! # => raises KeyError
+```
+
 Additional Resources
 --------------------