Updated readme 470

Author: itsmohitj

README.md

@@ -11,6 +11,7 @@
 300. [Longest Increasing Subsequence](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/lengthofLIS.py)
 349. [Intersection of Two Arrays](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/intersection.py)
 461. [Hamming Distance](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/hammingDistance.py)
+470. [Implement Rand10() Using Rand7()](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/rand10.py)
 589. [Preorder Traversal](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/preorder.py)
 595. [Big Countries](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/bigCountries.txt)
 617. [Merge Two Binary Trees](https://github.com/itsmohitj/Leetcode-Solutions/blob/master/mergeTress.py)