Random Seat assignment

https://github.com/practicalli/clojure-practicalli-content/issues/4

Take a functional / data oriented approach to solving this problem

Description

You want to randomly assign seating to a number of people for a fixed number of seats. Each seat is represented by an integer number between 1 and 30.

How do you randomly assign seats without choosing the same seat twice.

Loop / recur approach

Bad...

recursive function