Follow up of #31432.

The v4.3.1 has already released that includes Redis 4.0 support.
https://github.com/resque/resque-scheduler/blob/master/CHANGELOG.md#431---2017-11-20

Preserve original method visibility when deprecating a method

Suppress `warning: BigDecimal.new is deprecated` in activerecord

`BigDecimal.new` has been deprecated in BigDecimal 1.3.3
 which will be a default for Ruby 2.5.

Refer https://github.com/ruby/bigdecimal/commit/533737338db915b00dc7168c3602e4b462b23503

```
$ cd rails/activerecord/
$ git grep -l BigDecimal.new | grep \.rb | xargs sed -i -e "s/BigDecimal.new/BigDecimal/g"
```

- Changes made only to Active Record. Will apply the same change to
other module once this commit is merged.

- The following deprecation has not been addressed because it has been
reported at `ActiveRecord::Result.new`. `ActiveRecord::Result.ancestors`
did not show `BigDecimal`.

* Not addressed

```ruby
/path/to/rails/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb:34:
warning: BigDecimal.new is deprecated
```

* database_statements.rb:34

```ruby
ActiveRecord::Result.new(result.fields, result.to_a) if result
```

* ActiveRecord::Result.ancestors

```ruby
[ActiveRecord::Result,
 Enumerable,
 ActiveSupport::ToJsonWithActiveSupportEncoder,
 Object,
 Metaclass::ObjectMethods,
 Mocha::ObjectMethods,
 PP::ObjectMixin,
 ActiveSupport::Dependencies::Loadable,
 ActiveSupport::Tryable,
 JSON::Ext::Generator::GeneratorMethods::Object,
 Kernel,
 BasicObject]
```

This commit has been tested with these Ruby and BigDecimal versions

- ruby 2.5 and bigdecimal 1.3.3

```
$ ruby -v
ruby 2.5.0dev (2017-12-14 trunk 61217) [x86_64-linux]
$ gem list |grep bigdecimal
bigdecimal (default: 1.3.3, default: 1.3.2)
```

- ruby 2.4 and bigdecimal 1.3.0

```
$ ruby -v
ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-linux-gnu]
$ gem list |grep bigdecimal
bigdecimal (default: 1.3.0)
```

- ruby 2.3 and bigdecimal 1.2.8

```
$ ruby -v
ruby 2.3.5p376 (2017-09-14 revision 59905) [x86_64-linux]
$ gem list |grep -i bigdecimal
bigdecimal (1.2.8)
```

- ruby 2.2 and bigdecimal 1.2.6
```
$ ruby -v
ruby 2.2.8p477 (2017-09-14 revision 59906) [x86_64-linux]
$ gem list |grep bigdecimal
bigdecimal (1.2.6)
```

This commit fixes `deprecate` so that it preserves method visibility (like it
did previously when it was utilizing `alias_method_chain`).

When Module#prepend replaced alias_method_chain in a982a42d it caused deprecated
methods to always become public.

`alias_method_chain` had this bit of code:
https://github.com/rails/rails/blob/v5.0.6/activesupport/lib/active_support/core_ext/module/aliasing.rb#L40-L47
which preserved method visibility.

Without this fix, a workaround would be:

```ruby
class C8
  private

  def new_method
  end

  def old_method
  end
  deprecate :old_method, :new_method
  # workaround:
  instance_method(:old_method).owner.send(:private, :old_method)
end
```

Because the visibility needs to be fixed on the Module prepended by
MethodWrapper.

[ci skip] Add a space to comment in SidekiqAdapter

* I think it's better to have a leading space after the `#`
  denoting the start of the comment.

Expose Active Storage routes

Suppress expected exceptions by `report_on_exception` = `false`

* Ruby 2.4 introduces `report_on_exception` to control if it reports exceptions in thread,
this default value has been `false` in Ruby 2.4.

Refer https://www.ruby-lang.org/en/news/2016/11/09/ruby-2-4-0-preview3-released/

* Ruby 2.5 changes `report_on_exception` default value to `true`
since this commit https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?revision=61183&view=revision

This pull request suppresses expected exceptions by setting `report_on_exception` = `false`
it also supports Ruby 2.3 which does not have`report_on_exception`.

Make it same title in index and page [ci skip]

Fix active_storage installation failure when in engine

We need to pass scope attributes to `klass.new` to detect subclass.
Otherwise `subclass_from_attributes` can't detect subclass which is had
in scope attributes.

Fixes #18062.
Closes #18227.
Closes #30720.

Optimizing information_schema query for `foreign_keys`

Fix protected environments with symbols

Use CONSTRAINT_SCHEMA key for information_schema.referential_constraints.
See https://dev.mysql.com/doc/refman/5.7/en/information-schema-optimization.html.

```
> EXPLAIN SELECT fk.referenced_table_name AS 'to_table', fk.referenced_column_name AS 'primary_key', fk.column_name AS 'column', fk.constraint_name AS 'name', rc.update_rule AS 'on_update', rc.delete_rule AS 'on_delete' FROM information_schema.referential_constraints rc JOIN information_schema.key_column_usage fk USING (constraint_schema, constraint_name) WHERE fk.referenced_column_name IS NOT NULL AND fk.table_schema = 'activerecord_unittest' AND fk.table_name = 'fk_test_has_pk' AND rc.constraint_schema = 'activerecord_unittest' AND rc.table_name = 'fk_test_has_pk'\G
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: rc
   partitions: NULL
         type: ALL
possible_keys: NULL
          key: CONSTRAINT_SCHEMA,TABLE_NAME
      key_len: NULL
          ref: NULL
         rows: NULL
     filtered: NULL
        Extra: Using where; Open_full_table; Scanned 0 databases
*************************** 2. row ***************************
           id: 1
  select_type: SIMPLE
        table: fk
   partitions: NULL
         type: ALL
possible_keys: NULL
          key: TABLE_SCHEMA,TABLE_NAME
      key_len: NULL
          ref: NULL
         rows: NULL
     filtered: NULL
        Extra: Using where; Open_full_table; Scanned 0 databases; Using join buffer (Block Nested Loop)
2 rows in set, 1 warning (0.00 sec)
```

  - Add mention about `config.active_record.internal_metadata_table_name`
  - Add mention about `config.active_record.protected_environments`

  These changes prevent ignoring environments name of which is a `Symbol`
  ```
  config.active_record.protected_environments = ['staging', :production]
  ```

Currently, sanitize methods are private. So need `send` to use from
outside class.
However, sometimes want to use sanitize methods from outside Class when
want to generate SQL including multiple tables like search.
In order to avoid using `send` in such a case, changed methods to public.

Merge pull request #31405 from bogdanvlviv/fix-conflicts-counter_cache-with-touch-by-optimistic_locking

Fix conflicts `counter_cache` with `touch: true` by optimistic locking.

Fix doc typo [ci skip]

Quote colum_names when building select:

Revert "only install ffmpeg and mupdf on activestorage builds"

This reverts commit 6ec0ed67.

[ci skip] Fix Active Support Changelog about :race_condition_ttl

Remove stale comment about `ActiveRecord::SchemaDumper.ignore_tables` [skip ci]

Follow up of #31390.

Prevent race condition when resetting time stubs

If the current thread is preempted after the stub has been removed but
before the original method has been restored, then the other thread will
get a `NoMethodError` when it tries to call the method.

Using `silence_redefinition_of_method` instead of `undef_method` ensures
that either the stub or the original method is always in place.

Fix secrets command deprecation message

[ci skip] Update routing guide for Direct & resolved routes

* Added the direct method to routing guide.