title: Differentiate Restful routes and non-restful routes
body: <p>As far as I know, restful routes are routes that are based on REST architecture. And rails uses restful routes by default. <code>resource</code> keyword defines seven restful routes for us. While if I have to define a custom route, </p>
  
  <pre><code>resource :photos do
   memeber do
    get 'preview' #non-restful route
   end
  end
  </code></pre>
  
  <p>Now <code>preview</code> route is defined as non-restful route. Isn't it RESTful route?</p>
  
  <p><strong>My question is, how can we differentiate RESTful routes and non-RESTful routes? Can u give an example of a custom restful route and non-restful route.</strong> </p>