<div id="app">
   <div v-for="user in users">
       <div v-if="user.is_winner == 'winner'">
         <p> {{user.name}}</p>
       </div>
   </div>
</div>

new Vue({
  el: '#app',
  data: {
    users: [
    {
      "name": "Mike",
      "is_winner": "winner"
    },
    {
      "name": "Piter",
      "is_winner": "fail"
    },
    {
      "name": "Jow",
      "is_winner": "fail"
    },
    {
      "name": "Mike",
      "is_winner": "winner"
    }
]
  }
})