Cast number to string in Postgres

fixes #9170
Document change to clashing named route selection from journey commit 98a9802a
drop memory consumption and startup speed by switching to define_method
removing out of date comment.  :heart::heart::heart::heart::heart::heart::heart::heart::heart::heart::heart::heart: @pixeltrix
Change from each to each_value in http/parameters since we don't use key
Add regression tests for #9678

The bug with `ActiveSupport::TimeZone.parse` described in #9678 was
unwittingly fixed in 005d910 so add some tests to prevent regression.
fix typo in Active Record CHANGELOG [ci skip]
Merge pull request #9696 from senny/typo_in_changelog

fix typo in Active Record CHANGELOG [ci skip]
Add documentation to ActionDispatch::Request
Merge pull request #9694 from vipulnsward/change_from_each_to_each_value_in_http_params

Change from each to each_value in http/parameters since we don't use key
Http::Headers respects headers that are not prefixed with HTTP_
refactor, `Http::Headers` stores headers in env notation

Also:
cleanup, use consistent syntax for `Http::Header` and test.
allow headers and env to be passed in `IntegrationTest`.

Closes #6513.
`Http::Headers` respects dotted env vars, symbols, headers with numbers.
Merge pull request #9700 from senny/6513_integration_test_headers

rework passing headers and env variables in integration tests
Move some railties changelog entries to the top [ci skip]
Add support for generate scaffold password:digest

* adds password_digest attribute to the migration
* adds has_secure_password to the model
* adds password and password_confirmation password_fields to _form.html
* omits password entirely from index.html and show.html
* adds password and password_confirmation to the controller
* adds unencrypted password and password_confirmation to the controller test
* adds encrypted password_digest to the fixture
Merge pull request #9699 from rubys/scaffold_password_digest

Add support for generate scaffold password:digest

* adds password_digest attribute to the migration
* adds has_secure_password to the model
* adds password and password_confirmation password_fields to _form.html
* omits password from index.html and show.html
* adds password and password_confirmation to the controller
* adds unencrypted password and password_confirmation to the controller test
* adds encrypted password_digest to the fixture
Merge pull request #9690 from trevorturk/upgrade-notes

Rails 4 upgrade notes about clashing named route selection changes
Merge pull request #9698 from garethrees/request_documentation

Add documentation to ActionDispatch::Request