title: Mongoose validation err: Invalid schema configuration
body: <p>Trying to model a relationship between collections by embedding documents
  but when validating in the schema and setting "required" to True, here comes the err</p>
  
  <p>once I comment the required in genre object in movies schema the problem is solved
  but I want the validation</p>
  
  <pre><code>const Movie = mongoose.model(
    'Movies',
    new mongoose.Schema({
      title: {
        type: String,
        required: true,
        trim: true,
        minlength: 1,
        maxlength: 255
      },
      numberInStock: {
        type: Number,
        required: true,
        min: 0,
        max: 255
      },
      dailyRentalRate: {
        type: Number,
        required: true,
        min: 0,
        max: 255
      },
      genre: genreSchema
      required: true
    })
  );
  
  const genreSchema = new mongoose.Schema({
    name: {
      type: String,
      required: true,
      minlength: 5,
      maxlength: 50
    }
  });
  
  </code></pre>
  
  <p>TypeError: Invalid schema configuration: <code>True</code> is not a valid type at path <code>required</code></p>