updated readme

README.md

@@ -1199,6 +1199,19 @@ Read our [Contribution Guidelines](CONTRIBUTING.md) before you contribute.
 2. [`Encrypt`](./cipher/xor/xor.go#L10):  Encrypt encrypts with Xor encryption after converting each character to byte The returned value might not be readable because there is no guarantee which is within the ASCII range If using other type such as string, []int, or some other types, add the statements for converting the type to []byte.
 3. [`FuzzXOR`](./cipher/xor/xor_test.go#L108): No description provided.
 
+---
+</details>
+
+#####  Package railfence is a classical type of transposition cipher ref : https://en.wikipedia.org/wiki/Rail_fence_cipher
+
+---
+##### Functions:
+
+1. [`Encrypt`](.cipher/railfence/railfence.go#L7):  Encrypt encrypts a message using rail fence cipher
+2. [`Decrypt`](.cipher/railfence/railfence.go#L44):  decrypt decrypts a message using rail fence cipher
+3. [`TestEncrypt`](.cipher/railfence/railfence_test.go#L7) Test function for Encrypt
+4. [`TestDecrypt`](.cipher/railfence/railfence_test.go#L50) Test function for Decrypt
+
 ---
 </details>
 <!--- GODOCMD END --->