"meteor bundle" is deprecated

When running this I got the message "WARNING: 'bundle' has been deprecated. Use 'build' instead."
`meteor build` works slightly different, as you point it to a directory where it puts the `.tar.gz` file in.
Explicit size of the persistent disk

According to https://cloud.google.com/sdk/gcloud/reference/compute/disks/create you need to specify
Merge pull request #1 from lukasvan3l/master

Minor updates after running script myself