Added build workflow

.github/workflows/build.yml

@@ -0,0 +1,30 @@
+name: build
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  deliver:
+    runs-on: ubuntu-20.04
+    steps:
+    - name: Git checkout
+      uses: actions/checkout@v4
+
+    - name: Build the Docker image
+      run: docker build . -t sfgrp/taxonworks_rdoc_docker:latest --build-arg BUNDLER_WORKERS=3
+
+    - name: Login to DockerHub
+      uses: docker/login-action@v2
+      with:
+        username: ${{ secrets.DOCKERHUB_USERNAME }}
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+    - name: Push image to DockerHub
+      if: ${{ github.event_name != 'pull_request' }}
+      env:
+        DOCKER_TAG: '${{steps.docker_tag.outputs.result}}'
+      run: |
+        docker tag sfgrp/taxonworks:latest sfgrp/taxonworks:$DOCKER_TAG
+        docker push sfgrp/taxonworks:$DOCKER_TAG