title: HTTP.post_form in Ruby with custom headers
body: <p>Im trying to use Nets/HTTP to use <code>POST</code> and put in a custom user agent. I've typically used <code>open-uri</code> but it cant do <code>POST</code> can it?</p>
  
  <p>I use </p>
  
  <pre><code>resp, data = Net::HTTP.post_form(url, query)
  </code></pre>
  
  <p>How would I change this to throw custom headers in?</p>
  
  <p>Edit my query is:</p>
  
  <pre><code>query = {'a'=&gt;'b'}
  </code></pre>