title: Why Strong Params contains permitted: false
body: <p>I put in a <code>binding.pry</code> at the top of my controller's <code>update</code> action.  Once at that break point, I put in <code>params[:foo_bar]</code> to examine the <code>params</code> hash.  Here is what I get:</p>
  
  <pre><code>&lt;ActionController::Parameters {"utf8"=&gt;"✓", "_method"=&gt;"patch", "authenticity_token"=&gt;"123==", "foobar"=&gt;&lt;ActionController::Parameters {"barbazz_attributes"=&gt;{"start_date"=&gt;"08/27/2016", "end_date"=&gt;"08/29/2016", "id"=&gt;"89"}, "bazz_id"=&gt;"3", "abc_id"=&gt;"330", "bazzbazz_attributes"=&gt;{"0"=&gt;{"_destroy"=&gt;"1", "city_id"=&gt;"1669", "id"=&gt;"26"}, "1"=&gt;{"city_id"=&gt;"1681", "id"=&gt;"27"}, "2"=&gt;{"city_id"=&gt;"1672"}}} permitted: false&gt;, "cat_id"=&gt;["1", "1", "1"], "commit"=&gt;"Update FooBar", "controller"=&gt;"foo_bars", "action"=&gt;"update", "id"=&gt;"52"} permitted: false&gt;  
  </code></pre>
  
  <p>I assumed <code>permitted: false</code> is there because I did not whitelist some attributes.  I looked over the attributes and it appears to me that I did whitelist everything.  </p>
  
  <p>I am using Rails 5 if that happens to make any difference. </p>
  
  <p><strong>Question</strong>: What is an easy way to find out why the strong parameters are returning <code>params: false</code>.</p>