Added example to README

Author: namrun

Substitution_Cipher/README.md

@@ -8,3 +8,11 @@
 
 - The user is prompted to enter the message as well as the key according to which the message will be encrypted
 - The key will be accepted as a CSV file
+- Considering an example : 
+
+![Image](key.PNG)
+
+- This is the key as agreed upon both the parties
+- On running the script, the user is prompted to enter a message
+
+![Image](encrypt.PNG)

Substitution_Cipher/encrypt.PNG

@@ -1,3 +1,9 @@
-a,1
-2,b
- ,d
+a,w
+b,e
+c,2
+d,q
+t,z
+y,4
+m,s
+f,1
+o,l