PyLinking is a addon to Blender that is used for linking .py file from outside Blender to be run inside Blender.
This means that other tool then can be used to write the code. For instance Visual Studio Code. It is also possible to use GitHub in a very simple way since all our .py file can be located into a folder where GitHub can read/write.
For more information go to: https://www.blendermarket.com/products/pylinking