Migrations and legacy database

I'm developing a first rails application whith a legacy oracle
database. I only have access to the datbase at work, but I would still
like to work from home too.

I need to maintain 2 different "migration environments" in the same
migration files.

1) At work, I don't use the up or down methods in my migrations
classes.
2) At home I would like to "build a copy" of the oracle database" with
migrations and mySQL.

How can I accomplish this?
Thanks in advance for suggestions and help.