Revert "Add `ruby-debug` as development dependency."
Revert "Add `ruby-debug` as development dependency."

This reverts commit ac576e9612118490784aad3f1e16d43ddaf7bc17.

weby/reek,tansaku/reek,skywinder/reek,apuratepp/reek,HParker/reek,weby/reek,HParker/reek,skywinder/reek,troessner/reek,weby/reek,tansaku/reek,tansaku/reek,nTraum/reek,apuratepp/reek,nTraum/reek,apuratepp/reek,HParker/reek,andyw8/reek,chastell/reek,skywinder/reek,andyw8/reek,troessner/reek,andyw8/reek