update readme

Author: hogan-tech

README.md

@@ -133,7 +133,7 @@ The solutions are organized as follows:
 |0202|[Happy Number](https://leetcode.com/problems/happy-number/) | [Python](./0202-happy-number/0202-happy-number.py) | [Easy](./0202-happy-number/README.md) |
 |0203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/) | [C++](./0203-remove-linked-list-elements/0203-remove-linked-list-elements.cpp) | [Easy](./0203-remove-linked-list-elements/README.md) |
 |0205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/) | [Python](./0205-isomorphic-strings/0205-isomorphic-strings.py) | [Easy](./0205-isomorphic-strings/README.md) |
-|0206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/) | [Python](./0206-reverse-linked-list/0206-reverse-linked-list.py), [C++](./0206-reverse-linked-list/0206-reverse-linked-list.cpp) | [Easy](./0206-reverse-linked-list/README.md) |
+|0206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/) | [Python](./0206-reverse-linked-list/0206-reverse-linked-list.py), [C++](./0206-reverse-linked-list/0206-reverse-linked-list.cpp), [JavaScript](./0206-reverse-linked-list/0206-reverse-linked-list.js) | [Easy](./0206-reverse-linked-list/README.md) |
 |0207|[Course Schedule](https://leetcode.com/problems/course-schedule/) | [Python](./0207-course-schedule/0207-course-schedule.py) | [Medium](./0207-course-schedule/README.md) |
 |0208|[Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/) | [Python](./0208-implement-trie-prefix-tree/0208-implement-trie-prefix-tree.py) | [Medium](./0208-implement-trie-prefix-tree/README.md) |
 |0213|[House Robber II](https://leetcode.com/problems/house-robber-ii/) | [C++](./0213-house-robber-ii/0213-house-robber-ii.cpp) | [Medium](./0213-house-robber-ii/README.md) |