private method doesn't work for singleton methods defined this way
Add tests to ActiveSupport:XmlMini to_tag method
additional note about routes in functional tests for engines [ci skip]
add include_hidden option to collection_check_boxes helper
Save has_one associations only if record has changes

Prevents save related callbacks such as `after_commit` being
triggered when `has_one` objects are already persisted and have no
changes.
Don't load test env by default
Fix insertion of records for hmt association with scope, fix #3548
Only use BINARY for mysql case sensitive uniqueness check when column has a case insensitive collation.
Auto-generate stable fixture UUIDs on PostgreSQL.
Fixes: #11524
[Active Record] Renamed private methods create_record and update_record

 This is to ensure that they are not accidentally called by the app code.
 They are renamed to _create_record and _update_record respectively.
 Closes #11645
Pass a base relation to build_default_scope when joining

This allows the default scope to be built using the current table alias.
Resolves #12770
typos fixes
Tweak Configuring Guide language

the fact that Rails is multi-thread by default is not very relevant. see https://github.com/rails/rails/pull/13998 [ci skip]
:scissors:

This commit also addresses rails/docrails#169 and rails/rails#14159
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.
Bump version of bcrypt gem
travis s/2.1.0/2.1.1
Merge pull request #14199 from arthurnn/travis_211

travis s/2.1.0/2.1.1
Merge remote-tracking branch 'chancancode/fix_instance_method_already_implemented'

Conflicts:
	activerecord/CHANGELOG.md
[skip ci] Fix test name typo in app generator tests.