Added export to exercise stub

Ben Ward · Ben Ward · commit 45aa3f32b8f2 · 2017-12-18T17:06:35.000Z
diff --git a/exercises/atbash-cipher/atbash-cipher.ts b/exercises/atbash-cipher/atbash-cipher.ts
@@ -1,4 +1,6 @@
 class AtbashCipher {
     public encrypt(plainText: string) { }
     public decrypt(cipherText: string) { }
-}
+}
+
+export default AtbashCipher
