ERROR: Error installing json: The ‘json’ native gem requires installed build tools. Please update your PATH to include build tools or download the DevKit from ‘http://rubyinstaller.org/downloads’ and follow the instructions at ‘http://github.com/oneclick/rubyinstaller/wiki/Development-Kit’ Para resolver o problema: 1) Download DevKit  http://rubyinstaller.org/downloads (DevKit-tdm-32-4.5.2-20110712-1620-sfx.exe) ou mais atual 2) Extraia DevKit para seu Path Ruby mais atual, no ....