add stackato.yml

```
app.0: module.js:340
app.0:     throw err;
app.0:           ^
app.0: Error: Cannot find module '/app/app/start'
app.0:     at Function.Module._resolveFilename (module.js:338:15)
app.0:     at Function.Module._load (module.js:280:25)
app.0:     at Module.runMain (module.js:492:10)
app.0:     at process.startup.processNextTick.process._tickCallback (node.js:244:9)
```