Running schema --add without --levels="" throws exception when filling in the levels in the prompt

[kylecannon]

[vagrant@www Elite]$ bin/vfmagento schema --add --levels="make,model,trim"

Done
[vagrant@www Elite]$ bin/vfmagento schema --add
Enter Levels, Comma Delim, [enter] for [make,model,year]::
make,model,year

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'value' cannot be null' in /var/www/www/.modman/Vehicle-Fits-Magento/app/code/local/Elite/vendor/kylecannon/magento/lib/Zend/Db/Statement/Pdo.php on line 234

PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'value' cannot be null in /var/www/www/.modman/Vehicle-Fits-Magento/app/code/local/Elite/vendor/kylecannon/magento/lib/Zend/Db/Statement/Pdo.php on line 228