Once you've created your documentation using roxygen headers, you need to build your documentation. 
You can use the document() function from the devtools package to generate your documentation, 
supplying the path to the package as the first argument. The generated documentation will appear 
in the man directory. Once you've documented your package, you can view the help files just like 
you can with any of your existing packages.


# Generate package documentation
document("datasummary")

# Examine the contents of the man directory
dir("datasummary/man")

# View the documentation for the data_summary function
help("data_summary")

# View the documentation for the weather dataset
help("weather")