Added Furnace Tracker to apps.json (#152)

Replaces PR #150, which wasn't editing the json file

Author: johnoestmannmusic

data/apps.json

@@ -127,6 +127,16 @@
       "repo": "FlexASIO"
     }
   },
+  {
+    "name": "Furnace",
+    "url": "https://github.com/tildearrow/furnace",
+    "description": "Tracker sequencer with a huge selection of game system chips",
+    "repository": {
+      "type": "GitHub",
+      "user": "tildearrow",
+      "repo": "furnace"
+    }
+  },
   {
     "name": "Giada",
     "url": "https://www.giadamusic.com/",