AVEF/imports/startup/server/postStartup/version.js

import SimpleSchema from 'simpl-schema';

let AppVersion = new Mongo.Collection('AppVersion');
let AppVersionSchema = new SimpleSchema({
	version: {
		type: Number,
		optional: false,
		defaultValue: 0
	}
});
AppVersion.attachSchema(AppVersionSchema);

try {
	let appVersions = AppVersion.find({}).fetch();
	let appVersion;
	
	if(!appVersions || appVersions.length == 0) {  //This will happen only when first creating a database.
		appVersion = {version: 0};
		appVersion._id = AppVersion.insert(appVersion);
	}
	else if(appVersions.length > 1) {  //This should never happen.  Remove all but the first app version.
		for(let i = 1; i < appVersions.length; i++) {
			AppVersion.remove(appVersions[i]._id);
		}
	}
	else {
		appVersion = appVersions[0];
	}
	
	
}
catch(err) {
	console.log("Caught an error while upgrading the app version: " + err);
	process.exit(1);
}