Add tasks for all the new languages

Task/Josephus-problem/Nim/josephus-problem.nim

@@ -0,0 +1,20 @@
+import sequtils, strutils, future
+
+proc j(n, k): string =
+  var
+    p = toSeq(0 .. < n)
+    i = 0
+    s = newSeq[int]()
+
+  while p.len > 0:
+    i = (i + k - 1) mod p.len
+    s.add p[i]
+    system.delete(p, i)
+
+  result = "Prisoner killing order: "
+  result.add s.map((x: int) => $x).join(", ")
+  result.add ".\nSurvivor: "
+  result.add($s[s.high])
+
+echo j(5,2)
+echo j(41,3)