Update GCE step to work with folders, instead of branches.
Update GCE step to work with folders, instead of branches.

GoogleCloudPlatform/getting-started-ruby,GoogleCloudPlatform/getting-started-ruby,remi/getting-started-ruby,remi/getting-started-ruby,GoogleCloudPlatform/getting-started-ruby,remi/getting-started-ruby,GoogleCloudPlatform/getting-started-ruby,remi/getting-started-ruby