Preparing for 4.1.6.rc1 release
Merge pull request #16349 from jmcnevin/master

Correctly determine if migration is needed.
Fixes the digits counter of AS's NumberToRoundedConverter

Zero has one digit, but Math.log10(0) returns -Infinity. The method
needs to special-case zero.

The patch adds a regression test that is not clearly related to the
underlying issue because digit_count is private and has no coverage.
Gray area.

This bug was uncovered by 60062cf.
Merge pull request #16649 from Agis-/pg-columns-for-distinct

Fix postgresql adapter #columns_for_distinct trimming whitespace it shouldn't
CHANGELOG & improvements to #16649

* Require either FIRST or LAST qualifier for "NULLS ..."
* Require whitespace before "NULLS ..."

Conflicts:
	activerecord/CHANGELOG.md
Merge pull request #16756 from huoxito/dont-mess-railties-default-order

Dont mess with default order engines load (4.1.6.rc1 regression)
Do not mark object as persisted after an association is saved

Callback order in Active Record objects are important. Users should not
define callbacks before the association definition or surprising
behaviours like the described at #3798 will happen. This callback order
dependency is documented at https://github.com/rails/rails/blob/31bfcdc77ca0d8cec9b5fe513bdc6f05814dd4f1/activerecord/lib/active_record/associations.rb#L1222-1227.

This reverts #15728.

Fixes #16620.

Conflicts:
	activerecord/test/cases/associations/has_many_associations_test.rb
Preparing for 4.1.6.rc2 release
Use latest 2.1 version of sprockets-rails
Preparing for 4.1.6 release
Merge branch '4-1-6' into 4-1-stable

Conflicts:
	activerecord/CHANGELOG.md
	activesupport/CHANGELOG.md