Work towards subscriptions

- Replace chi with gorilla/mux
- Write custom CORS rules
- Start on notification subscriptions

api/graphql/resolvers/notification.go

@@ -0,0 +1,27 @@
+package resolvers
+
+import (
+	"context"
+
+	"github.com/viktorstrate/photoview/api/graphql/auth"
+	"github.com/viktorstrate/photoview/api/graphql/notification"
+)
+
+func (r *subscriptionResolver) Notification(ctx context.Context) (notification.NotificationChannel, error) {
+
+	user := auth.UserFromContext(ctx)
+	if user == nil {
+		return nil, auth.ErrUnauthorized
+	}
+
+	notificationChannel := make(notification.NotificationChannel, 1)
+
+	listenerID := notification.RegisterListener(user, notificationChannel)
+
+	go func() {
+		<-ctx.Done()
+		notification.DeregisterListener(listenerID)
+	}()
+
+	return notificationChannel, nil
+}