title: Adding a key to the permitted params
body: <p>I have this:</p>
  
  <pre><code>  def some_params
      params.require(:person).permit(:name, :pass)
  </code></pre>
  
  <p>These params are under the key "person" in "params". How can I add a key from the top level of "params" to the list of permitted params? In total it should result into 3 keys of permitted params.</p>