NewFeedItemsRepository creates a new FeedItemsRepository.

NewFeedsRepository creates a new FeedsRepository.

NewSubscriptionsRepository creates a new SubscriptionsRepository.

NewUsersRepository creates a new UsersRepository.

FeedItemsRepository object capable of interacting with FeedItemsRepository.

FeedsRepository object capable of interacting with FeedsRepository.

SubscriptionsRepository object capable of interacting with SubscriptionsRepository.

UsersRepository object capable of interacting with UsersRepository.