Consider a built-in feed generator

Writing your own Atom XML requires knowledge of the Atom spec, and while it's well-defined format:

1. It's not something you might be comfortable with.
2. You have to know what you're doing when it comes to escaping values, especially if you're using `post.title | smarty`.
3. You might not care, you just want a feed so you can use Serif to write content.

So there should be a feed generated for you based on config options. The default setting will be _off_ but the `_config.yml` file generated by `serif new` can show the necessary settings.