auto update README.md

Author: eastsage

README.md

@@ -500,6 +500,7 @@
 |273710. ROOT 아이템 구하기|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/273710.%E2%80%85ROOT%E2%80%85%EC%95%84%EC%9D%B4%ED%85%9C%E2%80%85%EA%B5%AC%ED%95%98%EA%B8%B0/README.md)|
 |388352. 비밀 코드 해독|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/388352.%E2%80%85%EB%B9%84%EB%B0%80%E2%80%85%EC%BD%94%EB%93%9C%E2%80%85%ED%95%B4%EB%8F%85/README.md)|
 |389479. 서버 증설 횟수|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/389479.%E2%80%85%EC%84%9C%EB%B2%84%E2%80%85%EC%A6%9D%EC%84%A4%E2%80%85%ED%9A%9F%EC%88%98/README.md)|
+|42586. 기능개발|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/42586.%E2%80%85%EA%B8%B0%EB%8A%A5%EA%B0%9C%EB%B0%9C/README.md)|
 |42839. 소수 찾기|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/42839.%E2%80%85%EC%86%8C%EC%88%98%E2%80%85%EC%B0%BE%EA%B8%B0/README.md)|
 |43165. 타겟 넘버|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/43165.%E2%80%85%ED%83%80%EA%B2%9F%E2%80%85%EB%84%98%EB%B2%84/%ED%83%80%EA%B2%9F%E2%80%85%EB%84%98%EB%B2%84.java)|
 |59408. 중복 제거하기|[링크](./%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4/2/59408.%E2%80%85%EC%A4%91%EB%B3%B5%E2%80%85%EC%A0%9C%EA%B1%B0%ED%95%98%EA%B8%B0/%EC%A4%91%EB%B3%B5%E2%80%85%EC%A0%9C%EA%B1%B0%ED%95%98%EA%B8%B0.sql)|