DataController.swift

import UIKit
import CoreData
class DataController: NSObject {
    var managedObjectContext: NSManagedObjectContext
    override init() {
        // This resource is the same name as your xcdatamodeld contained in your project.
        guard let modelURL = Bundle.main.url(forResource: "userFlags", withExtension:"momd") else {
            fatalError("Error loading model from bundle")
        }
        // The managed object model for the application. It is a fatal error for the application not to be able to find and load its model.
        guard let mom = NSManagedObjectModel(contentsOf: modelURL) else {
            fatalError("Error initializing mom from: \(modelURL)")
        }
        let psc = NSPersistentStoreCoordinator(managedObjectModel: mom)
        self.managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
        self.managedObjectContext.persistentStoreCoordinator = psc
        DispatchQueue.global(priority: DispatchQueue.GlobalQueuePriority.background).async {
            let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
            let docURL = urls[urls.endIndex-1]
            /* The directory the application uses to store the Core Data store file.
            This code uses a file named "DataModel.sqlite" in the application's documents directory.
            */
            let storeURL = docURL.appendingPathComponent("userFlags.sqlite")
            do {
                try psc.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: nil)
            } catch {
                fatalError("Error migrating store: \(error)")
            }
        }
    }
}