non-trivial supervisor idioms?

[Daniel Goertzen]

I've read the documentation on supervision and have seen a few tutorials,
but they don't seem to move beyond the core concepts.  For example, what
happens if you want to check and optionally setup an mnesia schema during
startup...where should this code go?  In the supervisor init() or
start_link() function?  Should I have my supervisor create a worker process
whole sole job is to do this kind of setup and then dynamically add other
workers (or supervisors) to the supervisor with start_child()?

I have this feeling there are already idiomatic ways of doing this, and I'm
reinventing the wheel poorly and incompletely.

Any advice appreciated.  Thanks,
Dan.