title: Permit arbitrary number of integers with strong_params
body: <p>I'm thinking perhaps an array is the way to go, but I'm not sure how to only allow arrays of integers. Here's what I'm starting with:</p>
  
  <pre><code>def put_params
    params.require(:project).permit(technologies: [])[:technologies]
  end
  </code></pre>
  
  <p>I want to be able to accept an arbitrary number of technology IDs securely.</p>