title: Where should I place my middleware file for Rails 5.1?
body: <p>Previously I had my middleware under lib/middleware/my_middle_ware.rb</p>
  
  <p>However when doing this,</p>
  
  <pre><code>config.middleware.use MyMiddleWare
  </code></pre>
  
  <p>I receive a </p>
  
  <pre><code>NameError: uninitialized constant
  </code></pre>
  
  <p>Where is rails looking for the middleware? </p>