title: Missing devise routes helpers inside of rails engine views
body: <p>I'm building a Rails engine called Engrave.</p>
  
  <p>I have the engine mounted like so:</p>
  
  <pre><code># Routes.rb of the host app
  mount Engrave::Engine =&gt; "/engrave", :as =&gt; "engrave_engine"
  </code></pre>
  
  <p>Within this engine I have a controller called "PostsController". When I navigate to this controller to view a post like so: <code>/engrave/posts/1</code> I get this error:</p>
  
  <pre><code>undefined local variable or method `new_user_session_path'
  </code></pre>
  
  <p>The PostsController in the engine is inheriting from the engine controller, which is inheriting from the application controller, like so:</p>
  
  <pre><code>module Engrave
    class PostsController &lt; ApplicationController
    ...
  end
  
  class Engrave::ApplicationController &lt; ApplicationController
  end
  </code></pre>
  
  <p>The new_user_session_path is being defined by devise, which I have setup like:</p>
  
  <pre><code>devise_for :users
  </code></pre>
  
  <p>The call to new_user_session_path is in the <code>layouts/application.html.erb</code> template file in the <strong>host app</strong></p>
  
  <p>I cannot figure out why this route helper isn't available in this context. What am I doing wrong?</p>