Just copy/paste the video URL on its own line. Naked, no brackets or other Markdown code, like so:

 https://youtu.be/gO1B1-FEvrw

You can see how other people format their posts by visiting Hiveblocks. Here is your post, for example. You can see how other people formatted their work the same way. Just remove the hive/peakd/ecency/whatever part of the URL depending on your frontend, and replace it with "hiveblocks.com"