todos.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test</title>
    <link rel="stylesheet" type="text/css" href="./styles/mystyle.css">
</head>

<body>
    <div id="app">
        <h2>
            Add todo
        </h2>
        <form @submit.prevent="addTodo">
            <input v-model="newTodo" placeholder="Add todo">
            <button>
                Add the todo
            </button>
        </form>
        <h2>Todos:</h2>
        <ol>
            <li v-for="todo in todos">
                <label>
                    <input type="checkbox" v-on:change="toggle(todo)" v-bind:checked="todo.done">

                    <del v-if="todo.done">
                        {{ todo.text }}
                    </del>
                    <span v-else>
                        {{ todo.text }}
                    </span>
                </label>
                <button @click="deleteTodo(todo)">
                    &times;
                </button>
            </li>
        </ol>
    </div>
</body>
<script src="./scripts/vue.js"></script>
<script src="./scripts/myVue.js"></script>

</html>