18.3 .Rmd and .md

• Markdown (.md) files play nicely with CRAN, github & pkgdown sites
  
• However, as our README file should include examples, a .Rmd file would allow us to run R code
  
• One way to do this is use a .Rmd file as the main source file, which can then be rendered into a .md file
  
• As usual, there is a handy function in usethis:::
  • usethis::use_readme_rmd()