MyIsam/InnoDB: weird behaviour using migrations


I set up a development environment on HostingRails. I have my own
application under development, and set up a Tracks
( instance in a subdomain.

The thing that bothers me is:

I thought that, by default, Rails would use InnoDB as storage engine
(which is what I wanted, as I want to use transactions).

My Tracks installation has all its tables set up using InnoDB, except
schema_version which, oddly, uses MyIsam.
My own application has all its tables using MyIsam.

I don’t remember having specified the storage engine anywhere. Having
that not specified anywhere, where could it come from?

thanks for any hint.