Add preview build

.github/workflows/build-preview.yaml

@@ -0,0 +1,55 @@
+name: build-preview
+
+on: workflow_dispatch
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Read version from file
+        id: get_version
+        run: echo "VERSION=$(cat version.txt)" >> $GITHUB_ENV
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ vars.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ github.token }}
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build latest
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ./docker/default.Dockerfile
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          tags: |
+            ghcr.io/sissbruecker/linkding:preview
+          target: linkding
+          push: true
+
+      - name: Build latest-alpine
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ./docker/alpine.Dockerfile
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          tags: |
+            ghcr.io/sissbruecker/linkding:preview-alpine
+          target: linkding
+          push: true