Update docker.yml to optionally upload to DockerHub

.github/workflows/docker.yml

@@ -18,6 +18,11 @@ on:
         required: false
         default: false
         type: boolean
+      uploadToDockerHub:
+        description: 'upload image to DockerHub'
+        required: false
+        default: false
+        type: boolean
 
   workflow_dispatch:
     inputs:
@@ -26,10 +31,13 @@ on:
         required: false
         default: false
         type: boolean
+      uploadToDockerHub:
+        description: 'upload image to DockerHub'
+        required: false
+        default: false
+        type: boolean
 
 env:
-  REGISTRY: 'ghcr.io'
-  REPOSITORY: ${{ github.repository_owner }}
   REGISTRY_USERNAME: ${{ github.actor }}
   REGISTRY_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
@@ -61,11 +69,18 @@ jobs:
         run: |
           echo "IMAGE_NAME=${GITHUB_REPOSITORY#$GITHUB_REPOSITORY_OWNER/}" >> $GITHUB_ENV
 
+      - name: Print image names
+        run: |
+          echo ${{ inputs.uploadToDockerHub && format('restatedev/{0}', env.IMAGE_NAME) || '' }}
+
       - name: Extract metadata (tags, labels) for Docker
         id: meta
         uses: docker/metadata-action@v4
         with:
-          images: ${{ env.REGISTRY }}/${{ env.REPOSITORY }}/${{ env.IMAGE_NAME }}
+          images: | 
+            ghcr.io/restatedev/${{ env.IMAGE_NAME }}
+            ${{ inputs.uploadToDockerHub && format('restatedev/{0}', env.IMAGE_NAME) || '' }}
+
           # Note: We need this to generate the latest tag until we have a first stable release.
           # Check https://github.com/docker/metadata-action/issues/34
           flavor: |