title: Express router - :id?
body: <p>Real simple question guys: I see a lot of books/code snippets use the following syntax in the router:</p>
  
  <pre><code>app.use('/todos/:id', function (req, res, next) {
    console.log('Request Type:', req.method);
    next();
  });
  </code></pre>
  
  <p>I'm not sure how to interpret the route here... will it route '/todos/anything'? and then grab the 'anything' and treat is at variable ID? how do I use that variable? I'm sure this is a quick answer, I just haven't seen this syntax before.</p>