add youtube link for 70

Author: fishercoder1534

README.md

@@ -847,7 +847,7 @@ _If you like this project, please leave me a star._ ★
 |73|[Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_73.java)||Medium|
 |72|[Edit Distance](https://leetcode.com/problems/edit-distance/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_72.java)||Hard| 
 |71|[Simplify Path](https://leetcode.com/problems/simplify-path/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_71.java)||Medium| Stack
-|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_70.java)||Easy| DP
+|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_70.java)|[:tv:](https://youtu.be/ZMNRb9TYiQM)|Easy| DP
 |69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_69.java)||Easy|
 |68|[Text Justification](https://leetcode.com/problems/text-justification/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_68.java)||Hard|
 |67|[Add Binary](https://leetcode.com/problems/add-binary/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_67.java)||Easy|