update project structure

app/src/main/kotlin/day01/Day01.kt

@@ -1,5 +1,5 @@
 
-package org.example
+package day01
 
 import kotlin.io.println
 import kotlin.math.abs

app/src/main/kotlin/org/example/App.kt

@@ -1,15 +0,0 @@
-/*
- * This source file was generated by the Gradle 'init' task
- */
-package org.example
-
-class App {
-    val greeting: String
-        get() {
-            return "Hello World!"
-        }
-}
-
-fun main() {
-    println(App().greeting)
-}

app/src/test/kotlin/day01/Day01Test.kt

@@ -1,4 +1,4 @@
-package org.example
+package day01
 
 import kotlin.test.Test
 import kotlin.test.assertNotNull

app/src/test/kotlin/org/example/AppTest.kt

@@ -1,14 +0,0 @@
-/*
- * This source file was generated by the Gradle 'init' task
- */
-package org.example
-
-import kotlin.test.Test
-import kotlin.test.assertNotNull
-
-class AppTest {
-    @Test fun appHasAGreeting() {
-        val classUnderTest = App()
-        assertNotNull(classUnderTest.greeting, "app should have a greeting")
-    }
-}