chore(build): fix demo build

Author: christianalfoni

packages/demos/todomvc/package.json

@@ -8,7 +8,7 @@
 	"repository": "git+https://github.com/cerebral/overmind.git",
 	"scripts": {
     "start": "webpack-dev-server --port 4000",
-    "build": "",
+    "build": "webpack",
 		"typecheck": "tsc --noEmit",
 		"prepare": "npm run build",
 		"posttest": "npm run typecheck"