feat: 초기 프로젝트 설정 및 룰.md 파일 추가

api.hyungi.net/node_modules/validator/es/lib/rtrim.js

@@ -0,0 +1,15 @@
+import assertString from './util/assertString';
+export default function rtrim(str, chars) {
+  assertString(str);
+  if (chars) {
+    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#Escaping
+    var pattern = new RegExp("[".concat(chars.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'), "]+$"), 'g');
+    return str.replace(pattern, '');
+  }
+  // Use a faster and more safe than regex trim method https://blog.stevenlevithan.com/archives/faster-trim-javascript
+  var strIndex = str.length - 1;
+  while (/\s/.test(str.charAt(strIndex))) {
+    strIndex -= 1;
+  }
+  return str.slice(0, strIndex + 1);
+}