Today `rake db:schema:cache:dump` only supports dumping cache for a
single connection (`ActiveRecord::Base.connection`). This doesn't work
for apps with multiple databases.

This PR makes `DatabaseTasks` to provide an API for dumping schema cache
for any connection.

Add a quote to an SQL insert statement of schema migration

Trim some needless words off the lines and format the code
sample like we'd write in the Rails source.

Marked as private in 2afe5a1d and doesn't seem worth it
to mention the module name here.

Mark :GeneratedAssociationMethods also as private_constant

Bump license years for 2017

Per https://www.timeanddate.com/counters/firstnewyear.html, it's already
2017 in a lot of places, so we should bump the Rails license years to
2017.

[ci skip]

remove `skip_bundle` option from plugin generator

Because `bundle install` is not executed regardless of whether the option
is specified or not.

Ref: fbd1e98c

- After https://github.com/rails/rails/commit/64e5b897ac944a05a33275e3828a3d4047a6b457,
  only :GeneratedAssociationMethods was remaining to be marked as
  private constant, so marked it as well.
- Before:
        >> User.constants(false)
        => [:GeneratedAssociationMethods]
- After:
        >> User.constants(false)
        => []

Fix ActiveSupport::Inflector.pluralize behavior for words that consist of non-ASCII characters

(test only; the original bug was fixed by 1bf50bad)

Add missing word in activerecord/CHANGELOG.md

[ci skip]

Closes #14640

We want the actual order to be very predictable, so it's rightly defined
in code -- not with an on-the-fly tsort.

But we can do the tsort here, and then verify that it matches the
implemented ordering. This way we don't leave future readers guessing
which parts of the ordering are deliberate and which are arbitrary.

Allow log remote ip addres when config.action_dispatch.trusted_proxie…

Remove needless `ActiveSupport::Deprecation.silence`

Remove remaining ActiveRecord deprecations

Grammar linting in activerecord/CHANGELOG.md

[ci skip]

Fix grammar in AR CHANGELOG.md [ci skip]

Remove all ActiveRecord deprecations