[ci skip] Close the meta tag with '/>' instead of '>'

This change fixes the 42 instances of `end tag for "meta" omitted, but
OMITTAG NO was specified` error message that comes up when the full
railsguides are validated.

Full error list at
https://gist.github.com/prakashmurthy/9086679.
Pointing to latest guides [ci skip]
Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
releasing Rails no longer needs triggering docs generation by hand [ci skip]

GitHub is now able to notify tag creation, I have configured the webhook
for the docs server to receive that event. Therefore, we no longer need
to trigger docs generation manually when releasing.
Revert "Only lookup `config.log_level` for stdlib `::Logger`. Closes #11665."

This reverts commit e2b2539468e2f0109ca309ed9ade53edbcc156a2.

Conflicts:
	railties/CHANGELOG.md

We expect loggers to quack like stdlib logger. If log4r needs different
level= assignment, using a Logger-quacking wrapper is the way to do it.

Fixes #14114.
Merge pull request #14140 from WojtekKruszewski/optimize_foreign_key_for

Prevent foreign_key_for? from evaluating all attributes
Merge pull request #12774 from exAspArk/fix_uniqueness_on_relation

Fix validation on uniqueness
Conflicts:
	activerecord/CHANGELOG.md
Methods silence_stream/quietly are not thread-safe [skip ci]

State that on the doc.

[fixes #11954]
Merge pull request #14170 from kritik/master

there could be more than 10 nested records
Conflicts:
	actionview/CHANGELOG.md
`ActionDispatch::Head` was replaced by `Rack::Head`. Closes #14191.

See 449039a86d802871b707dfb51ac1ed96d53526f9 for the original commit.
Merge pull request #14182 from mecampbellsoup/fix_typo_in_url_helper_docs

[skip ci] Fixing typo in documentation: actionview/lib/action_view/helpers/url_helper.rb
Merge pull request #14177 from yahonda/skip_tests_if_duplicate_index_not_allowed

Skip test_migrate_revert_add_index_with_name for some databases
Fixed STI classes not defining an attribute method if there is a
conflicting private method defined on its ancestors.

The problem is that `method_defined_within?(name, klass, superklass)`
only works correclty when `klass` and `superklass` are both `Class`es.

If both `klass` and `superklass` are both `Class`es, they share the
same inheritance chain, so if a method is defined on `klass` but not
`superklass`, this method must be introduced at some point between
`klass` and `superklass`.

This does not work when `superklass` is a `Module`. A `Module`'s
inheritance chain contains just itself. So if a method is defined on
`klass` but not on `superklass`, the method could still be defined
somewhere upstream, e.g. in `Object`.

This fix works by avoiding calling `method_defined_within?` with a
module while still fufilling the requirement (checking that the
method is defined withing `superclass` but not is not a generated
attribute method).

4d8ee288 is likely an attempted partial fix for this problem. This
unrolls that fix and properly check the `superclass` as intended.

Fixes #11569.

Conflicts:
	activerecord/CHANGELOG.md
	activerecord/test/cases/attribute_methods_test.rb
	activerecord/test/schema/schema.rb
Bump version of bcrypt gem
Merge pull request #14210 from tjschuck/bcrypt_gem_rename_4-0-stable

Bump version of bcrypt gem in 4-0-stable
Merge pull request #14199 from arthurnn/travis_211

travis s/2.1.0/2.1.1

Conflicts:
	.travis.yml
HashWithIndifferentAccess#select working as intended

Before this commit, #reject returned a HashWithIndifferentAccess,
whereas #select returned a Hash. Now #select also returns a
HashWithIndifferentAccess.
Remove warnings on Ruby 2.1

Conflicts:
	activesupport/lib/active_support/hash_with_indifferent_access.rb
Replace "data store" with database [ci skip]

Active Record is specifically for databases. Refs #12101.
Fix OrderedHash.select to return self instance.

On ruby 2.1.1 the behavior of .select and .reject has changed.
They will return a Hash new instance, so we need to override them to
keep the instance object class.