How to install Railscasts?
Railscasts is available in the official Kodi repository which is included by default in Kodi. You can install this addon by going in Kodi to System >> Settings >> Addons >> Get Addons >> XBMC.org Addons or Kodi.tv Addons
About SuperRepo and Railscasts
SuperRepo does not maintain Railscasts. We only provide an automated index for Kodi users to have easy access to Railscasts and other addons for Kodi. We are not affiliated with the developers (Pawel Lenart) and do not provide help for this particular addon.