[plugin.Provider]1-1>[models.PGProvider]
[models.PGProvider]*-*>[models.PGMethod]
[models.PGMethod]*-1>[models.PGProvider]
[models.PGConfig]*-1>[models.PGProvider]
[models.Merchant]1-*>[models.PGConfig]
[models.Subscription]1-1>[models.PaymentMethod]
[models.Customer]1-*>[models.PaymentMethod]
[models.PaymentMethod]1-1>[models.PGMethod]