¿Por qué el paquete no instala JSON gem?

Recibo el siguiente error al intentar ejecutar cap production deploy. DEBUG [dc362284] Bundler::GemNotFound: Could not find json-1.8.1.gem for installation DEBUG [dc362284] An error occurred while installing json (1.8.1), and Bundler cannot continue. DEBUG [dc362284] Make sure that `gem install...