Validations for associative models sailsJs

I am trying to build a REST API on sailsjs v0.11.0, I am looking for a way to validate all POST requests. Validation works for simple models.

Simple model example: category.js

module.exports = {
    attributes: {
        name: {
            type: 'string',
            required: true,    // this works
            unique: true
        }
    }
}

Associative one to many model example where validation doesnt work:

Chapter.js

module.exports = {

    attributes: {
        name: 'string',
        categoryId: 'integer',
        pages: {
            type: 'string',
            required: true     // This doesnt work
        },
        owner: {
            model: 'Upload'
        }
    }

};

Upload.js

module.exports = {

    attributes: {
        draftId: 'integer',
        chapters: {
            collection: 'Chapter',
            via: 'owner'
        }
    }
};