Add Guides note to change cache name space as Entry data is incompatible between 3.2 and 4.0
Fix grammar in Rakefile markup [ci skip]
Fix sentence structure [ci skip]
Merge pull request #17932 from brooksreese/master

Fix grammar in Rakefile markup [ci skip]
Correctly respect subtypes for PG arrays and ranges

The type registration was simply looking for the OID, and eagerly
fetching/constructing the sub type when it was registered. However,
numeric types have additional parameters which are extracted from the
actual SQL string of the type during lookup, and can have their behavior
change based on the result.

We simply need to use the block form of registration, and look up the
subtype lazily instead.

Fixes #17935
Add `force: true` to tables created in PG tests

If the tests are interupted and the teardown block doesn't run, the
developer needs to delete these manually in order to be able to run the
tests again.
[ci skip] update rails version to 3.2.21
Mounted Rack apps should have default named routes based on app name

This fixes a regression in 4.2.0 from 4.1.8.

https://github.com/rails/rails/pull/17823 fixed a similar regression regarding _explicitly_ named routes for a mounted Rack app, but there was another regression for the default value.

With a route like:

    Rails.application.routes.draw do
      mount Mountable::Web, at: 'some_route'
    end

The "Prefix" column of rake routes gives the following:

- 4.1.8:         mountable_web
- 4.2.0.beta1-4: [nothing]
- 4.2.0.rc1:     [nothing]
- 4.2.0.rc2:     some_route   <- regression

This fixes the default to go back to being based off the name of the class like the docs specify: https://github.com/rails/rails/blob/785d04e3109f69d0b9b9f4732179592f0ef04e52/actionpack/lib/action_dispatch/routing/mapper.rb#L558-L560

Explicitly named routes still work correctly per https://github.com/rails/rails/pull/17823:

    Rails.application.routes.draw do
      mount Mountable::Web, at: 'some_route', as: 'named'
    end

- 4.1.8:         named
- 4.2.0.beta1-4: [nothing]
- 4.2.0.rc1:     [nothing]
- 4.2.0.rc2:     named
Merge pull request #17943 from jeremywadsack/doc_cache_importability

Add Guides note to change cache namespace
Merge pull request #17942 from yui-knk/fix/upgrading.md

[ci skip] update rails version to 3.2.21
Merge pull request #17944 from tjschuck/mounted_named_routes_regression

Mounted Rack apps should have default named routes based on app name