Merge pull request #624 from dmcg/master

Simplify Item and make items property in GildedRose immutable because it was in Java

Kotlin/src/main/kotlin/com/gildedrose/GildedRose.kt

@@ -1,6 +1,6 @@
 package com.gildedrose
 
-class GildedRose(var items: List<Item>) {
+class GildedRose(val items: List<Item>) {
 
     fun updateQuality() {
         for (i in items.indices) {

Kotlin/src/main/kotlin/com/gildedrose/Item.kt

@@ -1,7 +1,9 @@
 package com.gildedrose
 
-open class Item(var name: String, var sellIn: Int, var quality: Int) {
+open class Item(
-    override fun toString(): String {
+    var name: String,
-        return this.name + ", " + this.sellIn + ", " + this.quality
+    var sellIn: Int,
-    }
+    var quality: Int,
+) {
+    override fun toString(): String = "$name, $sellIn, $quality"
 }