auto update README.md

Author: CheChe903

README.md

@@ -116,6 +116,7 @@
 |2504. 괄호의 값|[링크](./%EB%B0%B1%EC%A4%80/Gold/2504.%E2%80%85%EA%B4%84%ED%98%B8%EC%9D%98%E2%80%85%EA%B0%92/README.md)|
 |2589. 보물섬|[링크](./%EB%B0%B1%EC%A4%80/Gold/2589.%E2%80%85%EB%B3%B4%EB%AC%BC%EC%84%AC/README.md)|
 |2636. 치즈|[링크](./%EB%B0%B1%EC%A4%80/Gold/2636.%E2%80%85%EC%B9%98%EC%A6%88/README.md)|
+|2668. 숫자고르기|[링크](./%EB%B0%B1%EC%A4%80/Gold/2668.%E2%80%85%EC%88%AB%EC%9E%90%EA%B3%A0%EB%A5%B4%EA%B8%B0/README.md)|
 |2800. 괄호 제거|[링크](./%EB%B0%B1%EC%A4%80/Gold/2800.%E2%80%85%EA%B4%84%ED%98%B8%E2%80%85%EC%A0%9C%EA%B1%B0/README.md)|
 |3190. 뱀|[링크](./%EB%B0%B1%EC%A4%80/Gold/3190.%E2%80%85%EB%B1%80/README.md)|
 |4179. 불！|[링크](./%EB%B0%B1%EC%A4%80/Gold/4179.%E2%80%85%EB%B6%88%EF%BC%81/README.md)|