Exisiting Website Changes (Angular JS, Postgres)

I have a simple Angular JS website (I have only minified code) with a Postgres DB. I need the website to be changed as per my new requirement, remove unwanted stuffs, add more functionalities. Add Inventory management inside the website. Complete cleaning of the site is required. Add the code to Private GitHub and do deployment plans and practices for the future.
*Note --> I only have Minified script, the developer must beautify it.