Add koans for partition function

src/koans/20_partition.clj

@@ -0,0 +1,18 @@
+(meditations
+  "To split a collection you can use the partition function"
+  (= '((0 1) (2 3)) (__ 2 (range 4)))
+
+  "But watch out if there is not enough elements to form n sequences"
+  (= '(__) (partition 3 [:a :b :c :d :e]))
+
+  "You can use partition-all to also get partitions with less then n elements"
+  (= __ (partition-all 3 (range 5)))
+
+  "If you need to, you can start each sequence with an offset"
+  (= '((0 1 2) (5 6 7) (10 11 12)) (partition 3 __ (range 13)))
+
+  "Consider padding the last sequence with some default values.."
+  (= '((0 1 2) (3 4 5) (6 :hello)) (partition 3 3 [__] (range 7)))
+
+  ".. but notice that they will only pad up to given sequence length"
+  (= '((0 1 2) (3 4 5) __) (partition 3 3 [:this :are "my" "words"] (range 7))))