Now have doors that you can walk though. No open/close animation yet.

assets/tiles.json

@@ -65,5 +65,13 @@
     "foreground": "color:BAD",
     "background": "color:BAD",
     "id": 8
+  },
+  "door_plain": {
+    "texture": "assets/textures/door_plain.png",
+    "display": 1087,
+    "light": 0,
+    "foreground": "tiles/fg:wall_plain",
+    "background": "tiles/bg:wall_plain",
+    "id": 9
   }
 }