{
  type: 'ADD_TODO',
  payload: {
    text: 'Do something.'
  }
}

{
  type: 'ADD_TODO',
  payload: {
    title: 'Do something.',
    priority: 'HIGH',
    completed: false
  }
}

{
  type: 'ADD_TODO',
  payload: {
    todo: {
      title: 'Do something.',
      priority: 'HIGH',
      completed: false
    }
  }
}