Added test to ensure that DescendantsTracker does not leak memory on singleton classes
Fix doc in Postgres database creation
add active model basics wip to guides/documents.yaml
support :unless_exist for FileCache
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.
Fix the install task
Correct error in Utils.normalize_path that changed paths improperly
Merge pull request #12619 from Veraticus/fix_utils_normalize_path

Correct error in Utils.normalize_path that changed paths improperly
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