Add tasks for all the new languages

Task/Mad-Libs/Nim/mad-libs.nim

@@ -0,0 +1,16 @@
+import rdstdin, re, algorithm, sequtils, strutils
+
+#let templ = readLineFromStdin "Enter your story: "
+const templ = """<name> went for a walk in the park. <he or she>
+found a <noun>. <name> decided to take it home."""
+
+echo "The story template is:\n", templ
+var fields = templ.findAll re"<[^>]+>"
+fields.sort(cmp)
+fields = deduplicate fields
+let values = readLineFromStdin("\nInput a comma-separated list of words to replace the following items\n  " & fields.join(",") & ": ").split(",")
+
+var story = templ
+for f,v in zip(fields, values).items:
+  story = story.replace(f, v)
+echo "\nThe story becomes:\n\n", story