Getting Started with Squarespace Developer Mode Using Git and Local Dev Server

How to get started with Squarespace Developer mode using the local development server and Git. If you run into a ''-bash squarespace-server command not found" error when trying to run the server, it's most likely a npm permissions configuration issue. Follow these directions: https://docs.npmjs.com/resolving-eacces-permissions-errors-when-installing-packages-globally.