title: Why is my Rails mountable engine not loading helper methods correctly?
body: <p>I've built a rails gem that mounts as an engine.</p>
  
  <p>The engine is scoped to it's own namespace.</p>
  
  <p>In the engine, there's an <code>MyEngine::ApplicationHelper</code> module which adds a bunch of view helper methods.</p>
  
  <p>In my application layout, I refer to some of these methods.</p>
  
  <p>When I first load any of the pages in development mode I get a <code>NoMethodError</code>, complaining that the method (defined in the gem's <code>ApplicationHelper</code>) doesn't exist.</p>
  
  <p>Once I edit <code>ApplicationController</code> within my app, the problem corrects itself.</p>
  
  <p>Something tells me this is down to the recent changes in Rails's auto-loading; I'm using Rails 3.2.2</p>
  
  <p>I can't for the life of me work out why this isn't working properly though :/</p>