title: Mongoose validation from custom schema
body: <p>I have a schema like this:</p>
  
  <pre><code>let schema1 = new Schema({
      code: String,
      translation: {}
  });
  </code></pre>
  
  <p>and anoter schema like this:</p>
  
  <pre><code>let schema2 = new Schema({
      content: String
  });
  </code></pre>
  
  <p>and for exemple, I want a validation on schema1.translation.en based on schema2.</p>
  
  <p>Because isn't possible to have dynamic key on object(according to my searches).</p>
  
  <p>Thanks in advance.</p>