load dotenv everywhere it's needed; postgresql pool pre ping

app/db.py

@@ -18,5 +18,9 @@ elif DATABASE_URL and DATABASE_URL.startswith("postgres+"):
 if not DATABASE_URL:
     raise ValueError("DATABASE_URL environment variable is not set or empty.")
 
-engine = create_engine(DATABASE_URL)
+engine = create_engine(
+    DATABASE_URL,
+    pool_recycle=3600,
+    pool_pre_ping=True
+)
 SessionLocal = sessionmaker(bind=engine)