More explicit instructions for new users

[drscotthawley]

Nick, this is a great tool, thanks for making it.

In trying to use it to build my own cv with it, I hit a number of problems which other new users could be spared with a bit more documentation such as what I've added.

I'm still not clear on how/where to obtain the output from running index.Rmd. It doesn't seem like I get any new or updated files uploaded to my github account. Nor do I notice any new versions of files in my cv/ directory. Where does the output end up (for example, if we set PDF_EXPORT to TRUE)?