title: Rails crop image with start point, width, and height
body: <p>I have a Ruby/Rails app and I 'm wondering if there is a way to crop an image starting at the <code>top left point</code>, and specifyinga  <code>width</code>, <code>height</code> and the <code>img-url</code> and get the cropped <code>.jpg</code> file?</p>
  
  <p>For example, something like:</p>
  
  <p><code>(x: 0, y: 50, width: 100, height: 200, img-url='http://xxxx', name:'test')</code>
  <code>=&gt; result: 'test.jpg'</code></p>