feat: subs and views

src/domain/subscription.py

@@ -0,0 +1,22 @@
+import uuid
+from typing import TYPE_CHECKING
+
+from sqlalchemy import BigInteger, ForeignKey
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from src import domain
+
+if TYPE_CHECKING:
+    from .purchase import Purchase
+
+
+class Subscription(domain.Base):
+    """Подписка пользователя в целевой канал через конкретный закуп."""
+
+    purchase_id: Mapped[uuid.UUID] = mapped_column(ForeignKey('purchases.id'), index=True)
+    user_telegram_id: Mapped[int] = mapped_column(BigInteger, index=True)
+    username: Mapped[str | None]
+    invite_link: Mapped[str] = mapped_column(index=True)  # По которой пришёл пользователь
+
+    # Relationship
+    purchase: Mapped['Purchase'] = relationship()