I have moddet the point in the config: to true!

"Options": {
    "Modded": true,

However, my server is shown in the community list.
I have already reinstalled Oxide and yet I am still shown in the community list.

What can that be?

If it shows under Community, either Oxide isn't installed, it's somehow cached on the client you are using, or there's something not updating Steam; none of which we can fix for you as Oxide doesn't handle your server listing, only adding the modded tag.

That is added by Oxide when you have it installed and modded set to true in the config.

I installed it and set it to true! 

is there any other way?

If it is set to true and Oxide is installed, then it's likely just a matter of waiting.

Okay thanks