Using Vue JS inside WordPress

I want to use Vue js inside my WordPress plugin. Here is my html markup:

<div class="wrap" id="vue-app">
   <h2>Add counter</h2>
   <p>{{ message }}</p>
</div>

and here is my js:

var data = {
    message: 'Test message...',
};

new Vue({
    el: '#vue-app',
    data: data
});

but it's not working! I have checked and both Vue js and my js files are loading correctly. I'm really confused, because when I paste this code inside a HTML file outside WordPress, it works!

via Chebli Mohamed