Add option to ensure all child tables of an inheiritance/partitioned table have rows

[sfrost]

In larger database environments, tables end up being partitioned up (in PostgreSQL using inheiritance and check constraints, with constraint exclusion). It's important when testing to ensure that new code works with these inheiritance / partitioned tables. Therefore, please add an option to ensure that all child tables of an inheiritance structure have at least one row (or, perhaps, that at least more than one table in an inheiritance scheme has data).

I'd be happy to help if you have any questions on how inheiritance or constraint exclusion in PostgreSQL work.

Neat tool, thanks for building it!