Delete is a function to delete a todo it receives a id and returns a int64 and a error.

Get is a function to get a todo it receives a id and returns a Todo and an error.

GetAll is a function to get all todos it receives nothing and returns a slice of Todo and an error.

Insert is a function to insert a todo it receives a Todo and returns an int64 and an error.

Update is a function to update a todo it receives an id and a Todo and returns an int64 and an error.

Todo is a struct to represent a todo.