added 13_challenge (#16)

* changes are made as per 13 challenge

* missing colon image

* missing quote image

* missing method image

* read me file

Looks good @mohanqxf2 - I am merging your code. Congrats! You just made your first open source contribution.

13_challenge/13_challenge.py

@@ -0,0 +1,34 @@
+"""
+We will use this script to teach Python to absolute beginners
+The script is an example of Fizz-Buzz implemented in Python
+
+The FizzBuzz problem: 
+For all integers between 1 and 99 (include both):
+    # print fizz for multiples of 3
+    # print buzz for multiples of 5 
+    # print fizzbuzz for multiples of 3 and 5"
+"""
+
+def fizzbuzz(max_num):
+    "This method implements FizzBuzz"
+
+    # adding some redundant declarations on purpose
+    # we will make our script 'tighter' in one of coming exercises
+    three_mul = 'fizz
+    five_mul = 'buzz'
+    num1 = 3
+    num2 = 5 
+
+    # Google for 'range in python' to see what it does
+    for i in range(1,max_num)
+        # % or modulo division gives you the remainder 
+        if i%num1==0 and i%num2==0:
+            print(i,three_mul+five_mul)
+        elif i%num1==0:
+            print(i,three_mul)
+        elif i%num2==0:
+            print(i,five_mul)
+
+#----START OF SCRIPT
+if __name__=='__main__':
+    fizzbuzzy(100)