You should put the code in a code block instead of an external link, as well as the gifs.
As others have said above, repl.it should not be used for hosting as you are abusing their service, I suggest you chance your tutorial to use a different site
A captcha can easily be made, I don’t know why you think it doesn’t exist.
I might be wrong but I’m pretty sure you can set permissions on a group of who can post on the group wall. So if you are trying to prevent scam bots from posting on the wall you can just set it so that only staff members can post.
I’m not by any stretch saying this is useless because it definitely for games that have recruitments (like Zoro’s Restaurant for example) but I’m just saying if you’re only doing this only for scam bots then you can just set group wall permissions.