Problem with mongoose-seeder

Hello, everyone!

Im in the beginning of project 11 on the Full Stack Javascript Techdegree. I'm having trouble using the mongoose-seeder package to get the information from data.json into the database.

Basically, this is what happens: I make sure to use the package after the database has started using the following code:

db.once('open', () => {
    console.log('Database connection successful');

  seeder.seed(data).then(function(dbData) {
      console.log(dbData);
  }).catch(function(err) {
      console.log(err);
  });
});

I then get this error:

TypeError: Cannot read property 'dropDatabase' of undefined

So, I read the docs again and adds the following object as the second argument to the seed() method.

{ dropDatabase: false }

That gets rid of the first error. But then I get this error: MissingSchemaError: Schema hasn't been registered for model "User".

I can not see how that makes sense. I have defined all the models in a models.js file that ends like this:

const User = mongoose.model('User', UserSchema);
const Course = mongoose.model('Course', CourseSchema);
const Review = mongoose.model('Review', ReviewSchema);

module.exports.User = User;
module.exports.Course = Course;
module.exports.Review = Review;

The models.js file is required in my app.js file at the top. I have defined the Schemas of course.

Anyone have any ideas as to what is going on here? Thanks in advance! :)