Add Github workflow for publishing to Docker manually

.github/workflows/publish-docker.yaml

@@ -0,0 +1,25 @@
+name: Publish Docker image
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Version (without 'v' prefix)'
+        required: true
+        type: string
+
+jobs:
+  publish-docker:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Log in to Docker
+      env:
+        DOCKER_PASSWORD: ${{ secrets.DOCKER_ACCESS_TOKEN }}
+      run: |
+        docker login -u ${{ secrets.DOCKER_USER }} -p $DOCKER_PASSWORD
+    - name: Build Docker image
+      run: docker build . --tag ${{ secrets.DOCKER_USER }}/reshape:${{ inputs.version }} --tag ${{ secrets.DOCKER_USER }}/reshape:latest
+    - name: Push Docker image
+      run: docker push --all-tags ${{ secrets.DOCKER_USER }}/reshape