Add D language version

d/test/GildedRoseUnitTests.d

@@ -0,0 +1,25 @@
+import GildedRose;
+
+unittest
+{
+    Item[] items = [ Item("Foo", 0, 0)];
+    auto app = new GildedRose(items);
+
+    app.updateQuality;
+
+    assert("fixme" == app.items[0].name);
+}
+
+void example()
+{
+    Item[] items = [
+        Item("+5 Dexterity Vest", 10, 20),
+        Item("Aged Brie", 2, 0),
+        Item("Elixir of the Mongoose", 5, 7),
+        Item("Sulfuras, Hand of Ragnaros", 0, 80),
+        Item("Backstage passes to a TAFKAL80ETC concert", 15, 20),
+        Item("Conjured Mana Cake", 3, 6),
+    ];
+    auto app = new GildedRose(items);
+    app.updateQuality;
+}