Listing 1.8: The new README file, README.md.

After creating the topic branch, we’ll edit it to make it a little more
descriptive. I prefer the Markdown markup language to the default RDoc
for this purpose, and if you use the file extension .md then GitHub will
automatically format it nicely for you. So, first we’ll use Git’s
version of the Unix mv (“move”) command to change the name, and then
fill it in with the contents of Listing 1.8: