Add roll snippet

Resolves #413

snippets/roll.md

@@ -0,0 +1,18 @@
+---
+title: roll
+tags: list,beginner
+---
+
+Moves the specified amount of elements to the start of the list.
+
+- Use slice notation to get the two slices of the list and combine them before returning.
+
+```py
+def roll(lst, offset):
+  return lst[-offset:] + lst[:-offset]
+```
+
+```py
+roll([1, 2, 3, 4, 5], 2) # [4, 5, 1, 2, 3]
+roll([1, 2, 3, 4, 5], -2) # [3, 4, 5, 1, 2]
+```