Fix cross platform issue

Author: sopa301

build.gradle

@@ -54,6 +54,7 @@ shadowJar {
 
 run{
     standardInput = System.in
+    enableAssertions = true
 }
 
 checkstyle {

src/main/java/bot/Bot.java

@@ -34,7 +34,7 @@ public class Bot {
      */
     public Bot() {
         this.ui = new Ui();
-        this.storage = new Storage("/data/tasks.txt");
+        this.storage = new Storage("data/tasks.txt");
         try {
             tasks = new TaskList(storage.load());
         } catch (LoadingException e) {