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
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]