How to use the sqreen.signup_track function in sqreen

} as UserDocument;
		// optional data
		if (profile.photos && profile.photos.length > 0) {
			newUser.thumb = profile.photos[0].value;
		}

		newUser.providers[provider].profile = profile._json; // save original data to separate field
		newUser.emails = uniq(emails);

		logger.info(ctx.state, '[AuthenticationApi.createOAuthUser] Creating new user.');

		newUser = await UserUtil.createUser(ctx, newUser, false);

		/* istanbul ignore if */
		if (process.env.SQREEN_ENABLED) {
			require('sqreen').signup_track({ email: newUser.email });
		}

		logger.info(ctx.state, '[AuthenticationApi.createOAuthUser] New user <%s> created.', newUser.email);
		await LogUserUtil.success(ctx, newUser, 'registration', {
			provider,
			email: newUser.email,
		});
		// new oauth user, clear provider cache since there might gonna be new user matches.
		await apiCache.invalidateProviderCache(ctx.state, provider);

		this.noAwait(async () => {
			await mailer.welcomeOAuth(ctx.state, newUser);
		});

		return newUser;
	}

// TODO make sure newUser.email is sane (comes from user directly)
		const existingUser = await state.models.User.findOne({
			$or: [
				{ emails: sanitize(postedUser.email) },
				{ validated_emails: sanitize(postedUser.email) },
			],
		}).exec();

		if (existingUser) {
			throw new ApiError('User with email <%s> already exists.', postedUser.email).warn().status(409);
		}
		const confirmUserEmail = config.vpdb.email.confirmUserEmail && !skipEmailConfirmation;
		const createdUser = await UserUtil.createUser(ctx, postedUser, confirmUserEmail);

		if (process.env.SQREEN_ENABLED) {
			require('sqreen').signup_track({ email: createdUser.email });
		}

		await LogUserUtil.success(ctx, createdUser, 'registration', {
			provider: 'local',
			email: createdUser.email,
			username: createdUser.username,
		});

		this.noAwait(async () => {
			// user validated and created. time to send the activation email.
			if (config.vpdb.email.confirmUserEmail) {
				await mailer.registrationConfirmation(ctx.state, createdUser);
			}
		});

		// return result

}).then(user => {

		if (config.vpdb.services.sqreen.enabled) {
			require('sqreen').signup_track({ email: user.email });
		}

		LogUser.success(req, user, 'registration', { provider: 'local', email: newUser.email, username: newUser.username });

		// user validated and created. time to send the activation email.
		if (config.vpdb.email.confirmUserEmail) {
			mailer.registrationConfirmation(user);
		}

		// return result now and send email afterwards
		if (testMode && req.body.returnEmailToken) {
			api.success(res, _.extend(UserSerializer.detailed(user, req), { email_token: user.email_status.toObject().token }), 201);

		} else {
			api.success(res, UserSerializer.detailed(user, req), 201);
		}

// TODO make sure newUser.email is sane (comes from user directly)
		let user = await state.models.User.findOne({
			$or: [
				{ emails: newUser.email },
				{ validated_emails: newUser.email },
			],
		}).exec();

		if (user) {
			throw new ApiError('User with email <%s> already exists.', newUser.email).warn().status(409);
		}
		const confirmUserEmail = config.vpdb.email.confirmUserEmail && !skipEmailConfirmation;
		user = await UserUtil.createUser(ctx, newUser, confirmUserEmail);

		if (process.env.SQREEN_ENABLED) {
			require('sqreen').signup_track({ email: user.email });
		}

		await LogUserUtil.success(ctx, user, 'registration', {
			provider: 'local',
			email: newUser.email,
			username: newUser.username,
		});

		// user validated and created. time to send the activation email.
		if (config.vpdb.email.confirmUserEmail) {
			await mailer.registrationConfirmation(ctx.state, user);
		}

		// return result now and send email afterwards
		if (testMode && ctx.request.body.returnEmailToken) {
			return this.success(ctx, assign(state.serializers.User.detailed(ctx, user), { email_token: (user.email_status as any).toObject().token }), 201);

}).then(user => {

				if (config.vpdb.services.sqreen.enabled) {
					require('sqreen').signup_track({ email: user.email });
				}

				LogUser.success(req, user, 'registration', { provider: provider, email: newUser.email });
				logger.info('[passport|%s] New user <%s> created.', logtag, user.email);
				mailer.welcomeOAuth(user);

				return user;
			});