Added test to ensure that DescendantsTracker does not leak memory on singleton classes
Add params option for button_to

The parameters are rendered as hidden form fields within the generated
form. This is useful for when a record has multiple buttons associated
with it, each of which target the same controller method, but which
need to submit different attributes.
pass app config to controller helper proxy

After this fix application config become available when calling helper outisde of view

config/application.rb

    #...
    config.asset_host = 'http://mycdn.com'
    #...

Somewhere else

    ActionController::Base.helpers.asset_path('fallback.png')
    # => http://mycdn.com/assets/fallback.png
Merge pull request #12622 from timsly/helpers-from-outside

pass app config to controller helper proxy
slice! should not remove default hash value/proc
update CHANGELOG
Fix typo: `has_many :pets`, not `pets :has_many`.
Merge pull request #12629 from Peeja/has_many-pets-typo

Fix typo: `has_many :pets`, not `pets :has_many`.
Merge pull request #12624 from timsly/master

update CHANGELOG
Improve the CHANGELOG entry [ci skip]
Merge pull request #12611 from antonio/slice_bang_honor_default_proc

Make slice! honor default hash value/proc
always check to see if methods exist after calling define_attribute_methods
Merge pull request #10471 from andyw8/button_to_params

Add params option for button_to

Conflicts:
	actionpack/CHANGELOG.md
Merge pull request #12635 from mperham/4-0-stable

Allow any version of BCrypt
Add CHANGELOG entry for #12635 [ci skip]
Merge pull request #12632 from al2o3cr/fix_race_for_attribute_methods

Always check to see if methods exist after calling define_attribute_methods
Merge pull request #8491 from igagnidz/master

Issue #8442
Improve the test code for #8422

* Remove unneeded comments.
* Use key? instead of keys.include?.
Avoid unnecessary catching of Exception instead of StandardError (converting Exceptions into StandardErrors)
Merge pull request #12636 from kongregate/dont_rescue_Exceptions

Avoid unnecessary catching of Exception instead of StandardError (conver...