Whenever one of the mailers fires off if the body contains something like `link_to root_url` it gives this incredibly unhelpful error:

```
ActionView::Template::Error: No route matches {}

```

The trace either is useless or points to that `link_to` method. Since it's also very unsearchable here I am asking on stack overflow.

**UPDATE 1:** To help, I've posted the terrifying `routes.rb` file: <https://gist.github.com/2955610>

**UPDATE 2:** In the console, `app.root_url` provides the correct return.

**UPDATE 3:** `link_to "whatever", root_url` works just fine. So strange!

**UPDATE 4:** It works fine in a regular rails view.

**UPDATE 5:** *FIXED* The `image_tag` now isn't providing a host in the email, outputting: `http://assets/...png`. Fffff.

**UPDATE 6:** I've narrowed it down to that I get the same error with (in console) `app.url_for`. I think it may be related.