Add ActionController::Renderers.remove.
Remove :timestamp column type

The `:timestamp` type for columns is unused. All database adapters treat
them as the same database type. All code in `ActiveRecord` which changes
its behavior based on the column's type acts the same in both cases.
However, when the type is passed to code that checks for the `:datetime`
type, but not `:timestamp` (such as XML serialization), the result is
unexpected behavior.

Existing schema definitions will continue to work, and the `timestamp`
type is transparently aliased to `datetime`.
Merge pull request #15184 from sgrif/sg-remove-timestamp-type

Remove :timestamp column type
Revert "Rewrite journey routes formatter for performance"

This reverts commit 5c224de9e110763ec7a0f01f5b604bcf81f40bfb.

Conflicts:
	actionpack/lib/action_dispatch/journey/visitors.rb

5c224de9e110763ec7a0f01f5b604bcf81f40bfb introduced a bug in the
formatter.  This commit includes a regression test.
fix escaping in generation
make the AST go from left to right, rather than right to left
Merge pull request #15178 from zuhao/refactor_actionpack_respond_with_test

Deregister csv renderer after test to prevent leak.
Add using_resouce_with_json to controller.
Merge pull request #15182 from zuhao/refactor_actionpack_respond_with_test_2

Un-define :to_json for Customer class after stubbing.
docs, `instantiate` expects `String` keys. [Rafal Piekarski & Yves Senn]

Closes #15122
Closes #15107
fix `rake test_sqlite3_mem`.

While running Sqlite3 memory tests I encountered the following error:

```
Finished in 69.416366s, 58.0267 runs/s, 162.3681 assertions/s.

  1) Error:
ActiveRecord::Migration::ChangeSchemaTest#test_add_column_with_timestamp_type:
NoMethodError: undefined method `type' for nil:NilClass
    /Users/senny/Projects/rails/activerecord/test/cases/migration/change_schema_test.rb:244:in `test_add_column_with_timestamp_type'

4028 runs, 11271 assertions, 0 failures, 1 errors, 1 skips
```

This was because the table `testings` was used in multiple test-cases.
This resulted in a wrongly cached schema on `ActiveRecord::Base.schema_chae`.

/cc @zuhao
Use generated binstubs in guides examples.

[ci skip]
Merge pull request #15192 from simi/guides-binstubs

Use generated binstubs in guides examples. [ci skip]
Fixed the inferred table name for HABTM within a schema

Fixes #14824.
Merge pull request #14965 from eric-chahin/issue_14824

Fixed the inferred table name of a HABTM auxiliar
Delegate `#type_cast` to injected type objects on SQLite3
Merge pull request #15197 from sgrif/sg-delegate-type-cast-sqlite3

Delegate `#type_cast` to injected type objects on SQLite3