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.
slice! should not remove default hash value/proc
update CHANGELOG
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...
Save association when primary key is manually set
Merge pull request #12621 from laurocaetano/fix_has_one_association_with_primary_key_set

Save association when primary key is manually set

Conflicts:
	activerecord/CHANGELOG.md
test to verify the `ActiveRecord::Store` behavior with PG's json type
`stored_attributes` need to be specific to a subclass.

Currently they are all stored globally in the same `Hash`.
This commit forces the creation of a per-class variable if necessary.

The behavior was exposed through the following test-case:

```
  1) Failure:
StoreTest#test_all_stored_attributes_are_returned [/Users/senny/Projects/rails/activerecord/test/cases/store_test.rb:151]:
--- expected
+++ actual
@@ -1 +1 @@
-[:color, :homepage, :favorite_food]
+[:resolution, :color, :homepage, :favorite_food]
```