sequel-rails does not detect migrations from other specified directories.

[Aryk]

In Rails (atleast in 4 and 5), you can specify multiple paths for db/migrate, for example if you have Rails engines:

https://content.pivotal.io/blog/leave-your-migrations-in-your-rails-engines

The Sequel::Migrator class does not work with multiple directories and would take significant refactoring (not sure if Jeremy, the maintainer of Sequel, wants to do that, so I did a relatively simple solution.

My suggestion to resolve this is to copy the files temporarily over to the db migrate directory and then delete them after the SequelRails::Migrations call is over.