Use gradle to build kotlin files

Use `gradle test` to run the unit tests.

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

@@ -0,0 +1,58 @@
+package com.gildedrose
+
+class GildedRose(var items: Array<Item>) {
+
+    fun updateQuality() {
+        for (i in items.indices) {
+            if (!items[i].name.equals("Aged Brie") && !items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+                if (items[i].quality > 0) {
+                    if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
+                        items[i].quality = items[i].quality - 1
+                    }
+                }
+            } else {
+                if (items[i].quality < 50) {
+                    items[i].quality = items[i].quality + 1
+
+                    if (items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+                        if (items[i].sellIn < 11) {
+                            if (items[i].quality < 50) {
+                                items[i].quality = items[i].quality + 1
+                            }
+                        }
+
+                        if (items[i].sellIn < 6) {
+                            if (items[i].quality < 50) {
+                                items[i].quality = items[i].quality + 1
+                            }
+                        }
+                    }
+                }
+            }
+
+            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
+                items[i].sellIn = items[i].sellIn - 1
+            }
+
+            if (items[i].sellIn < 0) {
+                if (!items[i].name.equals("Aged Brie")) {
+                    if (!items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+                        if (items[i].quality > 0) {
+                            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
+                                items[i].quality = items[i].quality - 1
+                            }
+                        }
+                    } else {
+                        items[i].quality = items[i].quality - items[i].quality
+                    }
+                } else {
+                    if (items[i].quality < 50) {
+                        items[i].quality = items[i].quality + 1
+                    }
+                }
+            }
+        }
+    }
+
+}
+

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

@@ -0,0 +1,3 @@
+package com.gildedrose
+
+data class Item(var name: String, var sellIn: Int, var quality: Int)