title: Grape API modify parameter presence error
body: <p>As you know, you can specify that a parameter is required in a route like so:</p>
  
  <p><code>requires :province, :type =&gt; String</code></p>
  
  <p>However, I would like to be able to change the error that is thrown and provide my own error JSON when the parameter is not given.</p>
  
  <p>How can I do this easily? I am fine with monkey patching.</p>
  
  <p>EDIT: I see at line 191 <code>rescue_from</code> and that looks like it could be helpful but I'm not sure how to use it.
  <a href="https://codeclimate.com/github/intridea/grape/Grape::API" rel="nofollow">https://codeclimate.com/github/intridea/grape/Grape::API</a></p>