I am having difficulty finding good examples of how to embed R Shiny Apps in a Slidify presentation. Ideally I would like to reference the external app.R file instead of recreating my existing code in the index.Rmd. 
Can anyone provide examples, include which widgets I need to include, and if I can also have data (as an excel file) accompany the embedded app (using a relative path?).

Is Slidify development still ongoing? Most posts I find are from 2 or more years ago.

Thanks

Tim