Who is Jack Ruby from Libra and what is their importance?

Jack Ruby is a strip club owner in Dallas. Ruby had a difficult childhood and he feels overly blessed to live in a country where he can come from humble beginnings and become a business owner. Ruby pays this country back by treating the police to food every few days and doing all he can to be a good citizen. However, Ruby's club is in danger of closing, due to a loan he cannot pay back. It is this loan that people use to convince Ruby to kill Oswald, forever keeping him from pointing fingers at the conspirators.