add include_hidden option to collection_check_boxes helper
Save has_one associations only if record has changes

Prevents save related callbacks such as `after_commit` being
triggered when `has_one` objects are already persisted and have no
changes.
Don't load test env by default
Only use BINARY for mysql case sensitive uniqueness check when column has a case insensitive collation.
Pass a base relation to build_default_scope when joining

This allows the default scope to be built using the current table alias.
Resolves #12770
Replace map.flatten with flat_map in actionpack
Replace map.flatten with flat_map in activerecord
Replace map.flatten with flat_map in railties
Make CSRF failure logging optional/configurable.

Added the log_warning_on_csrf_failure option to ActionController::RequestForgeryProtection
which is on by default.
Fix OrderedHash.select to return self instance.

On ruby 2.1.1 the behavior of .select and .reject has changed.
They will return a Hash new instance, so we need to override them to
keep the instance object class.
Add preventDefault() on click event
Merge pull request #14316 from the4dpatrick/master

Add preventDefault() on click event
Make sure we clean preview_interceptors

We should make sure we clean preview_interceptors after each test so they dont leaky to the next test
Merge pull request #14318 from arthurnn/clean_preview_interceptors

Make sure we clean preview_interceptors
Tests for indifferent access using full_messages_for. Closes #11916
added CSRF helper to rails guide documentation. Closes #11615. [ci skip]
docs, shorten CsrfHelper description and refer to security guide. [ci skip]
Make the rails:template rake task load initializers

Templates could rely on irregular inflections or external libraries for
instance so we should load the application's initializers when running
the rails:template task.

The introducing commit of this feature is f7f11361 ; the initializers
have never been loaded invoking this task.

Fixes #12133.
Merge pull request #14280 from joho/make_csrf_failure_logging_optional

Make CSRF failure logging optional/configurable.
Merge pull request #14244 from arthurnn/orderd_hash_select_fix

Fix OrderedHash.select to return self instance.