Describe Sync

[tooolbox]

At 4.9k stars, https://github.com/golang-migrate/migrate is easily the most popular migrations library for Go. One thing it doesn't support is applying migrations out-of-sequence, which has been discussed extensively in various issues on that repo.

Completely by accident, I stumbled across a mention that Kamimai has support for out-of-sequence migrations! From looking it over, it seems that Sync() does this. However, it's really not clear from the readme.

I think it would be helpful, and a strong differentiator of this library, to explain on the main page what Sync does, and specifically the fact that it can merge together migrations authored at different points in time, if indeed that's what it can do.

Thanks!