chore: initialize fullstack starter and team guidelines

backend/app/db/session.py

@@ -0,0 +1,16 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, sessionmaker
+from app.core.config import settings
+
+class Base(DeclarativeBase):
+    pass
+
+engine = create_engine(settings.database_url, pool_pre_ping=True)
+SessionLocal = sessionmaker(bind=engine, autoflush=False, autocommit=False)
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()