carrierwave shows examples using S3, RackSpace, and Google storage. Is it possible to setup a similar thing with digital ocean?
From looking at their docs and searching around, the only option I'm seeing (since physical integration is missing) is local using the file method. Of course, if you're looking to connect to a Droplet remotely, that's not a valid option. You could, however, setup a Droplet and create a solution in-app that would push the files to your Droplet once uploaded locally and from there, do whatever you need to do with them (i.e. serve, modify, etc).
It's not as simple as setting the configuration in-app as it is with AWS and Google Cloud, but it is one solution if you want to use a Droplet with your application.
Yes, I recently wrote a little tutorial on it here if you want to give it a go: https://medium.com/@erickhoury/uploading-images-from-rails-to-digitalocean-spaces-with-previewing-8e10f427a02b