I'm not sure why you would selfhost this, but you can if you want. Make sure you have Node.js already installed.
$ git clone https://github.com/FireStreaker2/GuessTheError.git
$ cd GuessTheError
$ npm i
For developing:
$ npm run dev
For production:
$ npm run build
$ npm start
If you would like to contribute, you can fork the repo and make a PR, or contact me via email @ suggestions@firestreaker2.gq