LatestVersion returns latest version from supplied migration steps.

Migrate migrates the storage to the latest version.

NewStepOnIndex creates new migration step with update and/or delete operation.

NewStepsChain returns new StepFn which combines all supplied StepFn into single StepFn.

ValidateVersions checks versions if they are in order n (where n min version value), n+1, n+2, n+3..

Version returns the current version of the storage.

WithItemDeleteFn return option with ItemDeleteFn set.

WithItemUpdaterFn return option with ItemUpdateFn set.