Zend certified PHP/Magento developer

How can I setup Google Drive for Mac to NEVER delete anything?

I would like to use Google Drive to back files up from my Mac, and I don’t want to worry about deletions.

What I would like is for any file I create to be backed up. If I delete it on my PC, I don’t want it to be deleted in Google Drive. If I delete it in Google Drive, I don’t want it deleted off my PC. I don’t want anything to be deleted that I haven’t explicitly commanded.

How can I setup my Google Drive backups to never delete anything unless I explicitly command it to?