Make pkgdown site generation easier

[Torvaney]

Currently, I am manually calling pkgdown::build_site locally and deploying to heroku via git. There should be an automated process that builds and deploys the pkgdown site when new commits are pushed to origin/master

[Torvaney]

Could easily do this with travis ci

[Torvaney]

• https://pkgdown.r-lib.org/reference/deploy_site_github.html
• https://www.r-bloggers.com/continuous-deployment-of-package-documentation-with-pkgdown-and-travis-ci/

[Torvaney]

Done!