These instructions will guide you through the process of setting up local, trusted websites on your own computer.
These instructions are intended to be used on macOS Sierra, but they have been known to work in El Capitan, Yosemite, Mavericks, and Mountain Lion.
NOTE: You may substitute the edit command for nano, vim, or whatever the editor of your choice is. Personally, I forward the edit command to Sublime Text:
alias edit="/Applications/Sublime\ Text.app/Contents/SharedSupport/bin/subl"