title: Set options to array field in Mongoose schema
body: <p>How can I pass options such as <code>required: true</code> or <code>default</code> to an <strong>Array field</strong>?</p>
  
  <p>See the documentation <a href="http://mongoosejs.com/docs/schematypes.html#arrays" rel="nofollow">here</a>, it only shows examples like this one:</p>
  
  <pre><code>ArrayOfString: [String]
  </code></pre>
  
  <p>But I want to be able to do something like this:</p>
  
  <pre><code>ArrayOfString: { type: [String], required: true, default: ['one', 'two', 'three'] }
  </code></pre>
  
  <p>Maybe thats valid, but there are no examples like that one in the documentation.</p>