ci: add GH build

.github/workflows/docker.yaml

@@ -0,0 +1,56 @@
+name: release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Check out repo
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Cache Docker layers
+        uses: actions/cache@v3
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+
+      - name: Login to GHCR Docker registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set outputs
+        run: |
+          echo "RELEASE_TAG=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV \
+          && echo "RELEASE_SHORT_COMMIT=$(git rev-parse --short HEAD)" >> $GITHUB_ENV
+
+      - name: Build and push image
+        uses: docker/build-push-action@v2
+        with:
+          context: ./
+          file: ./Dockerfile
+          platforms: linux/amd64
+          push: true
+          build-args: |
+            BUILD=${{ env.RELEASE_SHORT_COMMIT }}
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache
+          tags: |
+            ghcr.io/grassrootseconomics/urdt-term:latest
+            ghcr.io/grassrootseconomics/urdt-term:${{ env.RELEASE_TAG }}