Only use BINARY for mysql case sensitive uniqueness check when column has a case insensitive collation.
minor fix to 4.1 rel notes for begin_transaction joinable option [CI skip]
Completely remove potential global state leaks in ActiveModel tests.

ActiveModel tests can now be run in random order.
Merge pull request #14343 from garysweaver/master

minor fix to 4.1 rel notes for begin_transaction joinable option
Fixes STI when 2+ levels deep.

PR #14052 Added a regression where it was only looking for methods in one
level up, So when the method was defined in a 2+ levels up the
inheritance chain, the method was not found as defined.
register OID for PostgreSQL citex datatype [Troy Kruthoff & Lachlan Sylvester]

citext makes it possible to use AR Hash finders for case-insensitive matching as sql UPPER/LOWER functions are not needed.
Removed unnecessary command "application"
Merge pull request #11616 from arunagw/removed-application-command-rails

Removed command "application"
Merge pull request #14342 from zuhao/eliminate_global_state_leak_in_activemodel_tests

Eliminate global state leaks completely in ActiveModel tests
Merge pull request #12523 from lsylvester/pg_citext

Support for PostgreSQL citext data type.
`change_table` supports `citext`. Follow up to #12523.
comment why we are modifying global state. [ci skip]
Merge pull request #14345 from arthurnn/revert_14052

Fixes STI when 2+ levels deep.
Remove mocking on save, when not necessary
Merge pull request #14353 from arthurnn/remove_small_mock

Remove mocking on save, when not necessary
[ci skip] Add documentation for original_fullpath.
Merge pull request #14291 from laurocaetano/doc-for-original-fullpath

Add documentation for original_fullpath. [ci skip]
MySQL 5.6 and later supports microsecond precision in datetime.

You might want to branch it to include this only for 5.6, but
passing these values to < 5.6 doesn't cause issues either.
Test microsecond on mysql 5.6
Changelog entry for mysql56 microseconds