title: string interpolation Vue js
body: <p>I'm trying to combine a string and a prop to create a unique <code>id</code> for a bootstrap accordion.</p>
  
  <p>I want to combine "collapse" and {{ thread_ref }} to create something like: <code>id="collapse_321"</code> </p>
  
  <p>Vue gives me an error when I try to do this and says to use v-bind.</p>
  
  <p>I have tried that but that only accepts a string of the name of the prop/data, how can I combine a string and data?</p>