title: Saving numpy array in mongodb
body: <p>I have a couple of MongoDB documents wherein one my the fields is best represented as a matrix (numpy array). I would like to save this document to MongoDB, how do I do this?</p>
  
  <pre><code>{
  'name' : 'subject1',
  'image_name' : 'blah/foo.png',
  'feature1' : np.array(...)
  }
  </code></pre>