title: How to use webmock regex matcher?
body: <p>How to match a URL like:</p>
  
  <pre><code>http://www.example.com/foo/:id/bar
  http://www.example.com/foo/1/bar
  http://www.example.com/foo/999/bar
  </code></pre>
  
  <p>stub_request(:post, "www.example.com")</p>