When creating a range in ruby … will give you an inclusive range (including your final value) and … will give you an exclusive range (excluding your final value)
So
1…12 → [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
1…12 → [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
You can find more on ranges at:
http://www.ruby-doc.org/core/classes/Range.html
James.