In my Gemfile I specified ruby version 2.0.0:
ruby \'2.0.0\'
But my console tells me I have 2.1.0dev:
$ ruby -v ruby 2.1.0d
Go to your Gemfile and change the description there I just got the same problem and couldn't find a "working" solution. So I made my own.
source 'https://rubygems.org' ruby '2.0.0' #Change this one to this '2.1.0'
gem 'rails', '4.0.3'