[Feature]: Support ADD COLUMN PLACEMENT

[puzzledpolymath]

When altering tables we can add columns just fine, but lacking is the control to place columns, either at the start of a table or after another column. Without this functionality, those who like their tables organized and structured a particular way, have no options

Describe the solution you'd like

Solution involves developing necessary methods and or parameters to produce similar SQL.

ALTER TABLE `table` ADD COLUMN `one` ... FIRST;
ALTER TABLE `table` ADD COLUMN `modified_at` ... AFTER `created_at`;

[roxblnfk]

Would you like to implement it?

[puzzledpolymath]

Yes this and the upserting feature is something I can help implement

[puzzledpolymath]

I considered taking a look at this today, however running unit tests failed without any changes being made.
Given that https://github.com/cycle/migrations/blob/4.x/tests/Migrations/BaseTest.php#L198 implicitly marks parameter $database as nullable, makes me think this package hasn't been tested against recent versions of PHP?

After fixing with protected function dropDatabase(?Database $database = null): void a segmentation error is raised. I'm not sure if my local environment is at fault? However I was able to test and submit a PR against the cycle/database package without any issues.

[puzzledpolymath]

Regarding the issues ecountered above, whilst running tests - I narrowed down the issue to a particular test.

Cycle\Migrations\Tests\ExceptionsTest::testBadMigrationFile

The segfault would happen after the expected exception is thrown here:

https://github.com/cycle/migrations/blob/4.x/src/FileRepository.php#L145

I disabled Xdebug and the problem went away, later upgrading it from 3.4.3-1.fc42.remi.8.4 to 3.4.4-1.fc42.remi.8.4 also fixed the issue while allowing Xdebug enabled.

[puzzledpolymath]

cycle/database#226