Revert "tried to implement the unique id's for each car"

This reverts commit 3aef6036b7d349677bfa5ee471411ebb9fac82a4.
Removed price adjustment for milage, it was messing up lot_value

*edited the User stories due to the fact that the milage reduciton does NOT actually work as expected. I did leave what I thought would work but was throwing an error.