ThirtyCharactersNeededThirtyCharactersNeededThirtyCharactersNeeded
By the way, please do inform me if this is in the wrong section.
This forum is for support on projects that are actually on Roblox. Your post is about a website on heroku.
Making tutorials about web development is allowed, but getting support is not.
I don’t know where to direct you to learn about web development though. That’s not an area of development that I’m familiar with.
You may find this helpful:
On the Roblox side of things, I’d suggest having your game download a list of banned user IDs when the server starts and, for example, every minute.
When a player joins the server, check their user ID against the list downloaded from your external server and kick them if their ID appears in the list.
Your in-game ban command should allow you to specify which user to ban, kick them from the game, and send their user ID to your external server for storing in a database or file.
The web implementation would be entirely down to you; but don’t forget you have services like Trello or Airtable which can be used to create ban lists, admin, etc. They also provide a REST API which allows your game to communicate directly with your Trello boards.
Yes and no, the user is still asking about the HttpService part of it. I would say the post is relevant enough 
Use google sheets. There are many tutorials and resources to make using google sheets easy for banlists and other types of storage.