How to outsource a template js to a different file when using Handlebars.js

I have this template script

<script id="some-template" type="text/x-handlebars-template">
   {{#users}}
     {username}
     {email}
</script>

I want to out-source it to a file called "user_template.js" which will look like this:

   {{#users}}
     {username}
     {email}

and make in the main index.html this link:

<script id="some-template" type="text/x-handlebars-template" src="user_template.js"></script>

The problem is - it doesn't work - how do I do it?