coreos/docs — pull request #227 by alex-ethier (2014-06-08 06:00:00+00:00)
Title: When defining a CoreOS channel in config.rb, the value should be quoted.

If not, the following error happens:

There was an error loading a Vagrantfile. The file being loaded
and the error message are shown below. This is usually caused by
a syntax error.

Path: .../coreos-vagrant/Vagrantfile
Message: undefined local variable or method `beta' for main:Object"
or
Message: undefined local variable or method `alpha' for main:Object"