ci: push docker images to dockerhub too.

.github/workflows/test.yaml

@@ -30,6 +30,7 @@ jobs:
         uses: docker/setup-buildx-action@v1
 
       # https://github.com/docker/login-action
+      # https://github.com/docker/build-push-action/blob/master/docs/advanced/push-multi-registries.md
       - name: Login to Github Container Registry
         uses: docker/login-action@v1
         with:
@@ -37,13 +38,21 @@ jobs:
           username: ${{ github.repository_owner }}
           password: ${{ github.token }}
 
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
       # Generate Docker tags from Git tags.
       # https://github.com/docker/metadata-action
       - name: Generate Docker tags
         uses: docker/metadata-action@v3
         id: metadata
         with:
-          images: ghcr.io/${{ github.repository }}
+          images: |
+            docker.io/evazion/danbooru
+            ghcr.io/danbooru/danbooru
           tags: |
             type=sha,format=short,prefix=
             type=sha,format=long,prefix=