title: in Sinatra how do you make a "before" filter that matches all routes except some
body: <p>I have a Ruby Sinatra app and I have some code which I need to execute on all routes except for a few exceptions. How do I do this?</p>
  
  <p>If I wanted to execute the code on selected routes (whitelist style) I'd do this:</p>
  
  <pre><code>['/join', "/join/*", "/payment/*"].each do |path|
      before path do
          #some code
      end
  end
  </code></pre>
  
  <p>How do I do it the other way round though (blacklist style)? I want to match all routes except <code>'/join'</code>, <code>'/join/*'</code> and <code>'/payment/*'</code></p>