Build fails

Hi,

I have troubles with getting it started. I am getting:

```
..Error: ENOENT: no such file or directory
lstat 'MY_REPO/digital-garden/graph-data.json'
at Object.lstatSync (node:fs:1529:3)
```

I have just copies my md files to posts folder. Do they need to have a special content for publishing?

Thanks for hints