docs: Document thank you page

README.md

@@ -9,4 +9,5 @@ HTTP Foxxos
     - Each picture must be a 600x395 image. You may use a tool like GIMP to scale your image and add a black background.
 2. Run the command `cargo run --bin png` to regenerate all images, or `cargo run --bin png <CODE>` to generate a single image.
 3. In the file `/src/status.json`, move the code from the Unimplemented list to the Implemented list.
-4. Add a new file in `/templates/statuses` in the format `CODE.html.tera`. More details about the status file format can be found in [the README.md](/templates/statuses/README.md)
+4. Add a new file in `/templates/statuses` in the format `CODE.html.tera`. More details about the status file format can be found in [the README.md](/templates/statuses/README.md)
+5. Credit yourself! Add an entry to `/src/credits.json`