title: angularjs tagging functionality with @ symbol in a textarea
body: <p>I am creating a app where users can comment on something. So to type the comment I have provided a textarea. Now I want to provide users with tagging functionality. By tagging I mean than when <code>@</code> is typed in the textarea automatically a list of all the users be shown than the commenter can choose a user and that username will appear as @username. Characters after the <code>@</code> symbol should work as typeahead. For ex: If I type @ma than only those users whose usernames starts with <code>ma</code> must be shown. I have a backend API for this. The API will return the results based on the typed characters.</p>
  
  <p>How can I accomplish this in front-end ?</p>
  
  <pre><code>I am using angular js version 1.4.7
  bootstrap 3.3.5
  </code></pre>