Add GitHub Actions workflow for Docker Hub auto-build

.github/workflows/docker.yml

@@ -0,0 +1,22 @@
+name: Build & Push Docker Image
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: mauriceboe/nomad:latest