Update Installfest to include instructions for upgrading Ruby in Windows #656
Description
Heroku now only supports MRI versions 2.4.5, 2.5.3, and 2.6.1 but RailsInstaller only comes with 2.2.6 or 2.3.3.
In order for Windows users to deploy to Heroku, after running RailsInstaller, users will need to remove the Ruby version it came with and install one of the Heroku-compatible versions via RubyInstaller.
Instructions to do so need to be added to the Installfest docs.