I'm building a Rails engine called Engrave.

I have the engine mounted like so:

```
# Routes.rb of the host app
mount Engrave::Engine => "/engrave", :as => "engrave_engine"

```

Within this engine I have a controller called "PostsController". When I navigate to this controller to view a post like so: `/engrave/posts/1` I get this error:

```
undefined local variable or method `new_user_session_path'

```

The PostsController in the engine is inheriting from the engine controller, which is inheriting from the application controller, like so:

```
module Engrave
  class PostsController < ApplicationController
  ...
end

class Engrave::ApplicationController < ApplicationController
end

```

The new\_user\_session\_path is being defined by devise, which I have setup like:

```
devise_for :users

```

The call to new\_user\_session\_path is in the `layouts/application.html.erb` template file in the **host app**

I cannot figure out why this route helper isn't available in this context. What am I doing wrong?