feat: 초기 프로젝트 설정 및 룰.md 파일 추가

api.hyungi.net/node_modules/js-git/lib/find-common.js

@@ -0,0 +1,58 @@
+function oneCall(fn) {
+  var done = false;
+  return function () {
+    if (done) return;
+    done = true;
+    return fn.apply(this, arguments);
+  };
+}
+
+module.exports = findCommon;
+
+function findCommon(repo, a, b, callback) {
+  callback = oneCall(callback);
+  var ahead = 0, behind = 0;
+  var aStream, bStream;
+  var aCommit, bCommit;
+
+  if (a === b) return callback(null, ahead, behind);
+  repo.logWalk(a, onAStream);
+  repo.logWalk(b, onBStream);
+
+  function onAStream(err, stream) {
+    if (err) return callback(err);
+    aStream = stream;
+    aStream.read(onA);
+  }
+
+  function onBStream(err, stream) {
+    if (err) return callback(err);
+    bStream = stream;
+    bStream.read(onB);
+  }
+
+  function onA(err, commit) {
+    if (!commit) return callback(err || new Error("No common commit"));
+    aCommit = commit;
+    if (bCommit) compare();
+  }
+
+  function onB(err, commit) {
+    if (!commit) return callback(err || new Error("No common commit"));
+    bCommit = commit;
+    if (aCommit) compare();
+  }
+
+  function compare() {
+    if (aCommit.hash === bCommit.hash) return callback(null, ahead, behind);
+    if (aCommit.author.date.seconds > bCommit.author.date.seconds) {
+      ahead++;
+      aStream.read(onA);
+    }
+    else {
+      behind++;
+      bStream.read(onB);
+    }
+  }
+
+}