Flatten budget-app contents into repo root

backend/app/db.py

@@ -0,0 +1,20 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, sessionmaker
+
+from .config import settings
+
+_connect_args = {"check_same_thread": False} if settings.database_url.startswith("sqlite") else {}
+engine = create_engine(settings.database_url, connect_args=_connect_args, pool_pre_ping=True)
+SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()