Write a program that finds the summation of every number from 1 to num. The number will always be a positive integer greater than 0.
For example (Input -> Output):
2 -> 3 (1 + 2)
8 -> 36 (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8)
def summation(num)
(1..num).sum
end