Version 5.x+ is incompatible with Rubinius

[brendon]

With the removal of the check for Thread.respond_to?(:handle_interrupt), rubinius is now completely not supported.

5fa7700#diff-eedb03e31afb7582f8694232561cf424L78

rubinius/rubinius#2890

I guess either the docs need updating or that conditional needs to be added back wherever it was removed. I don't use Rubinius personally but am trying to get a test suite passing across ruby versions for a gem. PG have already dropped Rubinius support. Not sure what that means for the future of Rubinius and Rails?