Update README.md

Author: BedrockDigger

README.md

@@ -3,6 +3,6 @@
 
 A GitHub Action for building [Mastodon](https://github.com/mastodon/mastodon) with [Tangerine UI](https://github.com/nileane/TangerineUI-for-Mastodon).
 - Automatically checks for new Mastodon releases daily.
-- Pushes to any specified Docker Hub repository.
+- Pushes to any specified Docker Hub repository (`DOCKERHUB_NAMESPACE`/`DOCKERHUB_REPOSITORY`).
 
-Add `DOCKERHUB_NAMESPACE`, `DOCKERHUB_REPOSITORY`, `DOCKERHUB_TOKEN` and `DOCKERHUB_USERNAME` in Settings > Security > Secrets and variables > Actions > Secrets first before running.
+Add `DOCKERHUB_NAMESPACE`, `DOCKERHUB_REPOSITORY`, `DOCKERHUB_TOKEN` and `DOCKERHUB_USERNAME` in Settings > Security > Secrets and variables > Actions > Secrets first before running.