Adding sequences to postgresql DBMS via migration generator

Can somebody provide me with a code example of how to tell a migration
to add a sequence other than the default? I have been floundering
around with the books and online resources but cannot find a clear
example. I anticipate that some sort of option hash is invloved but I
cannot determin the correct syntax.

I imagine that it would go something like this:


t.column :my_sequence_name :sequence => ‘my_sequence_name’ ???

Is this supposed to work? What other options are there if it does?

Many thanks.
Jim

Note: I want to add and additional sequence, not rename the default.

Regards,
Jim