title: Check if current_user is the owner of a resource and allow edit/delete actions
body: <p><strong>Example:</strong></p>
  
  <p>User <strong>A</strong> (id=10) has created a <strong>photo</strong> resource</p>
  
  <pre><code>photo: (id: 1 user_id = 10, url: "http://...")
  </code></pre>
  
  <p>Now, if User <strong>B</strong> (id=20) go to this url: <code>/photos/1/edit</code> it can edit photo of user <strong>A</strong>!!!</p>
  
  <p><strong>Rails+Devise</strong> provides something for this by default? It seems it's a very common issue</p>
  
  <p>I just need to allow that any user can edit/delete ONLY resource it has created (where current_user == resource.user)</p>
  
  <p><strong>Using:</strong> Rails 4, Devise</p>
  
  <p><strong>Update:</strong> </p>
  
  <p>I think CanCan it's something too advanced. I don't need roles or restrict some actions to certain users</p>