Initial public release

Aurum — a self-hosted personal finance operating system: cash flow,
net worth tracking, budgets, goals, recurring payments, reports,
proactive alerts, and a compound-interest returns calculator, all
bilingual (RU/EN) and mobile-first. Ships as a three-container Docker
Compose stack (Postgres + FastAPI + nginx-served React frontend).

See README.md for setup and CONTRIBUTING.md for development.

backend/app/models/transaction.py

@@ -0,0 +1,35 @@
+"""A single money movement: income, expense, or a transfer between accounts."""
+from datetime import date as date_
+
+from sqlalchemy import Date, Enum, ForeignKey, Numeric, String, Text
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.db.base import Base
+from app.models.enums import TransactionType
+from app.models.mixins import TimestampMixin
+
+
+class Transaction(Base, TimestampMixin):
+    __tablename__ = "transactions"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    account_id: Mapped[int] = mapped_column(ForeignKey("accounts.id", ondelete="CASCADE"), nullable=False)
+    category_id: Mapped[int | None] = mapped_column(ForeignKey("categories.id", ondelete="SET NULL"), nullable=True)
+    # Destination account for TRANSFER-type rows only.
+    transfer_account_id: Mapped[int | None] = mapped_column(
+        ForeignKey("accounts.id", ondelete="SET NULL"), nullable=True
+    )
+
+    type: Mapped[TransactionType] = mapped_column(
+        Enum(TransactionType, name="transaction_type", native_enum=False, length=10), nullable=False
+    )
+    # Always stored positive; `type` carries the sign/direction.
+    amount: Mapped[Numeric] = mapped_column(Numeric(14, 2), nullable=False)
+    description: Mapped[str] = mapped_column(String(255), nullable=False)
+    merchant: Mapped[str | None] = mapped_column(String(150), nullable=True)
+    notes: Mapped[str | None] = mapped_column(Text, nullable=True)
+    date: Mapped[date_] = mapped_column(Date, nullable=False)
+
+    account: Mapped["Account"] = relationship(back_populates="transactions", foreign_keys=[account_id])
+    transfer_account: Mapped["Account | None"] = relationship(foreign_keys=[transfer_account_id])
+    category: Mapped["Category | None"] = relationship(back_populates="transactions")