`messages` has `default_proc` so calling `reject` causes the warning.

https://github.com/ruby/ruby/blob/v2_4_1/hash.c#L1335-L1337

Fix a failed AR test when running with OracleAdapter

CI against Ruby 2.3.4

Add missing backtick to deprecation message

https://www.ruby-lang.org/en/news/2017/03/30/ruby-2-3-4-released/

Fix example usage of ActiveRecord::Base.establish_connection [ci skip]

[ci skip]

Restore rails-ujs.js UMD module support

Move HashWithIndifferentAccess tests to separate file

`ActiveRecord::Base.establish_connection` accepts a single symbol argument to specify a named connection; a single string argument appears to be interpreted as a connection URI

Do not include default response headers for AC::Metal

Update comment in sanitizer helper test [skip ci]

Raise when using a bad symlink

The previously referenced file no longer appears to exist in the project.

In Rails 4.2, `ActionController::Metal` controllers did not include the
default headers from `ActionDispatch::Response`. However, through e16afe61, and a
general shift towards having `ActionController::Metal` objects contain
`ActionDispatch::Response` objects (instead of just returning an array
of status, headers, and body), this behavior was lost. This PR helps to
restore the original behavior by having `ActionController::Metal`
controllers generate Response objects without the default headers, while
`ActionController::Base` now overrides the factory method to make sure
its version does have the default headers.

Add an alias for reverse_merge to with_defaults

In the context of controller parameters, reverse_merge is commonly used
to provide defaults for user input. Having an alias to reverse_merge
called with_defaults feels more idiomatic for Rails.

Add comma and change verb.

[ci skip]

add hint on after_action filters

Load only needed records on ActiveRecord::Relation#inspect

Fix the example code for `Rails.groups` [ci skip]

CI against Ruby 2.2.7

FinderMethods#fourty_two docs cite proper source

Fix link to rails-ujs

[ci skip]

`Rails.groups` contains `Rails.env` that is inspected as String.

https://github.com/rails/rails-ujs is merged into actionview in favor of https://github.com/rails/rails/pull/28098.
[skip ci]

https://www.ruby-lang.org/en/news/2017/03/28/ruby-2-2-7-released/

silly method gets a silly doc fix, 
or I'm missing an even sillier joke and I'm about to get schooled.

BUT I'm pretty sure this is some serious Beaudrillard simulacrum, though.
I'm just doing my part to spread the gospel of Douglas Adams.

Adds a hint that ``after_action``-callbacks are not executed when an
exception was raised in the rest of the request cycle. The
``before_action`` section mentions "If there are additional filters
scheduled to run after that filter, they are also cancelled." but this
is IMO not sufficient.

Fix `primary_keys` across multiple schemas

This CHANGELOG.md is a continuation of the 5-1-stable one, there
shouldn't be any duplicate entries.

[ci skip]

Make `driven_by` overridable