JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/1.0.28/vue.min.js"></script>
<div id="app">
  <div class="col-sm-offset-3 col-sm-4 clearfix text-center">
    <h4>On Each Day of The Week</h4>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox1" v-model="schedules[0].by_days" value="1"> M
    </label>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox2" v-model="schedules[0].by_days" value="2"> Tu
    </label>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox3" v-model="schedules[0].by_days" value="3"> W
    </label>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox4" v-model="schedules[0].by_days" value="4"> Th
    </label>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox5" v-model="schedules[0].by_days" value="5"> F
    </label>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox6" v-model="schedules[0].by_days" value="6"> Sa
    </label>
    <label class="checkbox-inline">
      <input type="checkbox" id="inlineCheckbox7" v-model="schedules[0].by_days" value="7"> Su
    </label>
    <div class="clearfix"></div>
  </div>
</div>

JavaScript

new Vue({
    el: '#app',
    data: {
        schedules: [
        	{
          	'by_days': ["1", 2, 3]
          }
        ]
    }
})