todolist ngrx refactor models

appState.ts

import { ITodoList } from './todoList';
import { ITodo } from './todo';

export interface IAppState {
  todoLists: ITodoList[];
  currentTodoList: number;
  todos: ITodo[];
}

export const INITIAL_STATE: IAppState =  {
  todoLists: undefined,
  currentTodoList: undefined,
  todos: undefined
};

todo.ts

export interface ITodo {
  id?: number;
  listId: number;
  todo: string;
  complete: boolean;
}

todoList.ts

export interface ITodoList {
  id: number;
  listName: string;
}