Make git workflow more robust

[isteves]

Connect to GitHub

1. usethis::use_git()
2. usethis::use_github()

#TODO: how to deal with errors

If use_github gets an authentication error, then switch to terminal and use git directly: git push origin master

https://community.rstudio.com/t/difficulty-using-usethis-use-github/5579

[isteves]

This solution works for me:

cred <- git2r::cred_ssh_key(
  publickey = "~/../.ssh/id_rsa.pub",
  privatekey = "~/../.ssh/id_rsa"
)
use_github(credentials = cred)

http://happygitwithr.com/ssh-keys.html#git2r-or-some-other-tool-cant-find-ssh-keys-on-windows