title: How do I override _path helpers in rails properly?
body: <p>I have a model called <em>resource</em> in my rails app and in need of modifying the return value of the helper *resource_path*, I've read some docs and SO Q/A and they're generally suggesting put the customized helper in *app/helpers/application_helper.rb*. The thing bothers me is that what do I do with the old auto generated helper? should I do something like</p>
  
  <pre><code>undef resource_path
  </code></pre>
  
  <p>before I go ahead and write my own helper? Currently I have a *resource_path* method defined within <em>ApplicationHelper</em>, interestingly when I open rails console, app.resource_path and helper.resource_path giving me different result.</p>
  
  <p>Also, I'd like to hear a deeper explanation on how *_path* helpers implemented and how they are related to *link_to* helper, as the source code are kinda hard to read with so many meta programming techniques involved</p>