I think the author of that repo misunderstands what a rainbow table is. I only quickly skimmed the code, but it doesn't seem to do anything related to rainbow tables.
On top of that, a rainbow table (if that is what you're looking to use) would not help here. The password is both very long and salted.
The repo was just a quick example of how one would use a rainbow table to crack the password. Yes, the fact that it only generates a simple rainbow table means that it isn't the holy grail to the exercise, but the idea of a rainbow table is that someones out there have already been running and generating a rainbow table for many years.
On top of that, a rainbow table (if that is what you're looking to use) would not help here. The password is both very long and salted.