Given a user account on GitHub, say, ‘eddelbuettel’, and a repository
‘drat’, we can infer an top-level repostory URL as such as
https://eddelbuettel.github.io/drat/ by supplying only the username (as
the rest is inferred by defaults). This allows us to create easily
useable, identifiable and shareable per-user repositories---without
the user having to create and administer a webserver anywhere.
Two higher level functions then allow both insertion of (source or
binary) packages, as well as addition of a given drat repository to an
R session so that package in the repository can be accesses.