Update d.json

Added a new plugin - Diffy.

repository/d.json

@@ -314,6 +314,17 @@
 				}
 			]
 		},
+		{
+			"name": "Diffy",
+			"details": "https://github.com/zsong/diffy",
+			"labels": ["diff", "compare", "difference", "comparison"],
+			"releases": [
+				{
+					"sublime_text": "*",
+					"details": "https://github.com/zsong/diffy/tree/master"
+				}
+			]
+		},
 		{
 			"name": "Dimmed Color Scheme",
 			"details": "https://github.com/uonick/dimmed",