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.
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.
Merge pull request #14325 from robin850/issue-12133

Make the rails:template rake task load initializers