Add tasks for all the new languages

Task/Binary-digits/Idris/binary-digits.idris

@@ -0,0 +1,18 @@
+module Main
+
+binaryDigit : Integer -> Char
+binaryDigit n = if (mod n 2) == 1 then '1' else '0'
+
+binaryString : Integer -> String
+binaryString 0 = "0"
+binaryString n = pack (loop n [])
+  where loop : Integer -> List Char -> List Char
+        loop 0 acc = acc
+        loop n acc = loop (div n 2) (binaryDigit n :: acc)
+
+main : IO ()
+main = do
+  putStrLn (binaryString 0)
+  putStrLn (binaryString 5)
+  putStrLn (binaryString 50)
+  putStrLn (binaryString 9000)