Hi Sofanit,

All you have to do is  to save you example dataset as a .rda file the /data/ folder of your package. The easiest way to do this is via the save() function. You will then have to push your update on Github. 

If you use R-studio it should be fairly easy to document your dataset with the roxygen package.

You can find a good tutorial on how to add data in a package on this website:http://r-pkgs.had.co.nz/data.html