Cache survey data by city

In order to reduce the loading time on the dashboard, we are thinking about implementing a way to cache the survey data by city. I came across the diskCache object that's part of Shiny, which can be found here: https://shiny.rstudio.com/reference/shiny/1.2.0/diskCache.html. It caches objects to a local directory, and these objects can be set and retrieved using keys. It seems like the simplest way to do it, but we could also try using Redis.