Todo Model

The Todo class has several fields that represent the properties of a todo item:

• id: This is a string that is used to store the document ID of the todo item from a database (such as Firestore.) This field is optional and can be null.

• createdAt: This is a DateTime object that represents the date and time when the todo item was created.

• title: This is a string that represents the title of the todo item.

• isReminder: This is a boolean that indicates whether the todo item has a reminder set or not.

• isDone: This is a ...