added postgres support

src/baby_monitor/models/db/user.py

@@ -21,7 +21,9 @@ class User(Base):
     username = Column(String, unique=True, index=True, nullable=False)
     hashed_password = Column(String, nullable=False)
     is_admin = Column(Boolean, default=False, nullable=False)
-    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    created_at = Column(
+        DateTime(timezone=True), default=datetime.utcnow, nullable=False
+    )
 
     def __repr__(self) -> str:
         return f"<User(id={self.id}, username='{self.username}')>"