title: How do I create a document with an empty relation list
body: <p>I have a model like this:</p>
  <pre><code>const schema = new Schema({
    name: String,
    age: String,
    skills: [{
      type: ObjectId,
      ref: &quot;Skill&quot;,
    }],
  });
  
  module.exports = model(&quot;User&quot;, schema);
  </code></pre>
  <p>And a controller to create such documents:</p>
  <pre><code>async create({ body }, res) {
      try {
        const user = new User(body);
        const newUser = await user.save();
        return res.status(200).send(newUser);
      } catch (err) {
        return res.status(400).send(boom.boomify(err));
      }
  },
  
  </code></pre>
  <p>Then I try to create an empty document for this model by sending such request from frontend:</p>
  <pre><code>axios.post('/users', {
    name: '',
    age: 18,
    skills: []
  });
  </code></pre>
  <p>And it's crashing with the error of:</p>
  <blockquote>
  <p>User validation failed: skills: Cannot read property 'indexedPaths' of undefined</p>
  </blockquote>
  <p>What I want to do is to create an empty document so I could fill all the props (as well as the relations <strong>skills</strong>) later by updating that document.</p>