Added workflow to build docker image

.github/workflows/docker-build.yml

@@ -0,0 +1,15 @@
+name: Docker build
+
+on: [push]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          push: false
+          tags: bastantoine/backup-me:latest