This function inserts the given (source or binary) package file
into the given (local) package repository and updates the
index. By setting the commit option to TRUE, one can
then push to a remote git code repository. If the
git2r package is installed, it is used for
the interaction with the git repository; otherwise the git
shell command is used.
An aliased function insert is also available, but not
exported via NAMESPACE to not clobber a possibly unrelated
function; use it via drat:::insert().
The function also checks for a top-level index.html file to ensure
external tests against the repository (as for example done by CRAN if you
list the repository as an ‘Additional_repositories’ in a package)
do not return a ‘404’ error. If missing, a simple one-line example is
shown.