Nodejs per client mongoose schema - json

Question

So I want to offer my users the ability to upload CSV and from that generate a mongoose schema, that I store in the DB against that user. When the user logs in, they can create a collection according to their personal schema. Using generate-schema I am able to create a json schema which looks like:
{
"_id" : ObjectId("596a872cd1e59c6135fa7b2e"),
"title" : "Product Set",
"type" : "array",
"items" : {
"type" : "object",
"properties" : {
"booktitle" : {
"type" : "string"
},
"bookid" : {
"type" : "string"
},
"bookauthor" : {
"type" : "string"
}
},
"required" : [
"booktitle",
"bookid",
"bookauthor"
],
"title" : "Product"
},
"＄schema" : "http://json-schema.org/draft-04/schema#"
}
and store that in my schema collection. All good...
When I want to create a collection according to that schema, and store data in it using mongoose, I have tried to retrieve the schema from the database (which works) and then do
var generatedSchema = GenerateSchema.mongoose(response)
I then create a model from that with:
var Model = db.models.Product || db.model('Product', generatedSchema);
and create an item from that model
var item = new Model({
"_id": new ObjectID(),
booktitle: 'The Godfather',
bookid: 'abc123',
bookauthor: 'Mario Puzo'
});
and save it:
item.save(function(err, response) { ... })
I don't get any errors but when I save it, in the collection I just see:
{
"_id" : ObjectId("5970b1a584d396d7a2241eba"),
"items" : {
"required" : []
},
"__v" : 0
}
Can anyone point me in the right direction as to why this isn't working? My suspicion is I am using the wrong type of schema to create the model.
If someone has an answer to the above, how would you then go about creating methods on the schema, as you would if the schema was static and part of the codebase of the application?
Thanks