Merge pull request #17588 from djpowers/patch-1

[ci skip] Use American English and replace "behaviour" with "behavior".

guides/source/upgrading_ruby_on_rails.md

@@ -421,7 +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.
@@ -795,7 +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.