diff --git a/.gitignore b/.gitignore
index 474fdf77..da940a1d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 test.txt
 
+*.log
\ No newline at end of file
diff --git a/app.js b/app.js
index ef41a4cd..e5b6b400 100644
--- a/app.js
+++ b/app.js
@@ -2,7 +2,7 @@
 const fs = require('fs');
 const fileName = './test.txt';
 for (let count = 0; count < 30; count++) {
-    fs.appendFile(fileName, 'おはようございます\n', 'utf8');
-    fs.appendFile(fileName, 'こんにちは\n', 'utf8');
-    fs.appendFile(fileName, 'こんばんは\n', 'utf8');
+    fs.appendFile(fileName, 'おはようございます\n', 'utf8', () => {});
+    fs.appendFile(fileName, 'こんにちは\n', 'utf8', () => {});
+    fs.appendFile(fileName, 'こんばんは\n', 'utf8', () => {});
 }