Allow adding versions manually

[marijoo]

This introduces the possibility to add versions manually by using createVersion() on the versionable model. This is useful if one would like to tweak a models history later on and add historical data from the past.

$post->createVersion(); // will do nothing if the model is not dirty

$post->title = 'Changed title';
$post->createVersion(); // will create a version even if versioning is disabled and the model changes are not stored (yet)

$post->createVersion(['title' => 'Changed title']); // will create a version of the model merged with the given attributes

$post->createVersion(['title' => 'very old version'], '1970-01-01') // allows to create historic versions

Because users are allowed to tweak a models version history later on the sorting has changed quite a bit. We are no longer sorting by Version.id alone. Instead created_at and id are taken into account to find previous and next versions.

And because $model->versions isn’t guaranteed to be sorted correctly anymore $model->history does exactly that:

$post->versions;
// ['id' => 1, 'title' => 'First title', 'created_at' => '2022-10-07 12:15:00']
// ['id' => 2, 'title' => 'Changed title', 'created_at' => '2022-10-07 12:30:00']
// ['id' => 3, 'title' => 'very old version', 'created_at' => '1970-01-01 00:00:00']

$post->history;
// ['id' => 2, 'title' => 'Changed title', 'created_at' => '2022-10-07 12:30:00']
// ['id' => 1, 'title' => 'First title', 'created_at' => '2022-10-07 12:15:00']
// ['id' => 3, 'title' => 'very old version', 'created_at' => '1970-01-01 00:00:00']

Please check out the tests I've added which will give a good overview of the changes.

[overtrue]

@marijoo Thanks.