HI rushikesh,
Take a look here: https://docs.mendix.com/developerportal/deploy/run-mendix-docker-image and related articles.
Its not required to have a GIT repository to make this happen.
Another note: The diffing in Mendix is currently done in the modeler, per document text based and not visual. Which will be improved in the near future. Building your own diffing based on GIT would be a waist of time ;-)