Update ddp.md

Author: seankross

ddp.md

@@ -8,7 +8,7 @@ permalink: /ddp/
 - [ggvis and rmarkdown slides with interactive plots](http://qua.st/ggvis-shiny-html5-slides/)
 - [Shiny app to simulate 401K growth with interactive plots](http://www.mephistosoftware.com/shiny/401k_simulator/)
 - [Shiny Video Tutorials Playlist on Youtube](http://www.youtube.com/playlist?list=PL6wLL_RojB5xNOhe2OTSd-DPkMLVY9DfB)
-- [Tutorial on writing Shiny simulation apps](http://homer.shinyapps.io/sim_tutorial_Rmd)
+- [Tutorial on writing Shiny simulation apps](https://github.com/homerhanumat/shinyTutorials)
 
 ## Comprehensive Notes