Add ghcr build

.github/workflows/build.yml

@@ -0,0 +1,33 @@
+name: Build and push Docker image
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  build:
+    name: Build docker container
+
+    runs-on: ubuntu-latest
+
+    permissions:
+      packages: write
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Login to GitHub Container Registry
+        if: ${{ github.ref == 'refs/heads/master' }}
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build Docker image (and push on master)
+        uses: docker/[email protected]
+        with:
+          push: ${{ github.ref == 'refs/heads/master' }}
+          tags: ghcr.io/cthit/findit:latest