Based on this blogpost.
Install with Homebrew:
$ brew install postgresql@14(The version number 14 needs to be explicitly stated. The @ mark designates a version number is specified. If you need an older version of postgres, use postgresql@13, for example.)
This is how to copy your files from a given git branch to a new empty branch, using a squash merge.
This example will copy files from branch old-branch to target-branch
# First be sure, that you don't have uncommitted working changes. They will be deleted
# Checkout a new empty branch without history
git checkout --orphan target-branch