Scheduled refresh with on-premise gateway when the data source is an R script

I built a report in desktop that uses as its data source an R script.  The script pulls data from a database, manipulates the data quite a bit, and ultimately produces a data frame that is used by Power BI as the data source.  I've published this report to the cloud.

I'm now trying to figure out how to schedule a refresh.  I can manually perform a refresh in desktop (which basically re-runs the R script and pulls the same-named data frame I originally selected when I set it up), but I cannot figure out how R scripts that are present in the desktop .pbix file are represented in the cloud (if they even are), or what type of data source to add to the on-premises gateway.

Help!