Ember CLI / resource / wp-api slug

For practice, and because the word 'post' is too confusing these days, I'm creating a resource called thought(s) - I'm getting some wp-json with the WordPress API (so the 'posts' are 'thoughts') - I'm setting the path to /wordpress with the intention of getting urls like this: http:/site.com/wordpress/thought-slug - I'm nesting the resources, so that the path is relative to the parent.

What I don't understand is how I know what the 'dynamic' : part is - and how I choose it. In the tutorials I've found, it's always post_id or something, but the specifics aren't explained.

I have a thoughts.js with {{#link-to 'thought'}}go{{/link-to}}, and a thought.js - and I've done this in the tutorials, so I'm just missing an understanding of how that dynamic part works...

Help :/

router.js

Router.map(function() {

  // WordPress
  this.resource('thoughts', {
    path: '/wordpress' },
    function() {
      this.resource('thought', {
        path: ':thought???'
      });
    }
  );

});

export default Router;