Add parallel runtime dependency to gemspec
Add parallel runtime dependency to gemspec

peruukki/wraith,OfflineAudio/wraith,saulirajala/wraith,sideci-sample/sideci-sample-wraith,LessonPlanet/wraith,jzinkdi/wraith,BBC-News/wraith,deividmarques/wraith,OfflineAudio/wraith,guimoreira07/wraith,jaredstehler/wraith,marciovicente/wraith,deividmarques/wraith,saulirajala/wraith,jzinkdi/wraith,peruukki/wraith,deividmarques/wraith,jaredstehler/wraith,webdev1001/wraith,guimoreira07/wraith,webdev1001/wraith,jaredstehler/wraith,jzinkdi/wraith,guimoreira07/wraith,BBC-News/wraith,adouglas/wraith,adouglas/wraith,LessonPlanet/wraith,LessonPlanet/wraith,adouglas/wraith,BBC-News/wraith,marciovicente/wraith,sideci-sample/sideci-sample-wraith,peruukki/wraith,webdev1001/wraith,marciovicente/wraith,saulirajala/wraith