Mongoose ODM model creation problems
I would suggest you have a models directory within which you have a file defined for each model. In the model file export the model itself.
In models/Registry.js -
module.exports = mongoose.model('Registry', RegistrySchema);
And in your app.js, just require all the model files -
var fs = require('fs'), modelPath = __dirname + '/models';fs.readdirSync(modelPath).forEach(function(file) { require(modelPath + '/' + file);});
Have a look at the MEAN stack boilerplace structure - https://github.com/linnovate/mean/tree/master/app
Also have a look at this article to understand how require works - http://openmymind.net/2012/2/3/Node-Require-and-Exports/