Add github workflow

Author: matsuu

.github/workflows/docker.yml

@@ -0,0 +1,60 @@
+name: ci
+
+on: [push]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: docker/setup-qemu-action@v2
+      - uses: docker/setup-buildx-action@v2
+      - uses: docker/login-action@v2
+        if: github.ref_type == 'tag'
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - uses: docker/login-action@v2
+        if: github.ref_type == 'tag'
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: docker/metadata-action@v4
+        id: meta
+        with:
+          images: |
+            ${{ github.repository_owner }}/nethack
+            ghcr.io/${{ github.repository_owner }}/nethack
+          flavor: |
+            latest=true
+          tags: |
+            type=semver,pattern={{version}}
+      - uses: docker/build-push-action@v3
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.ref_type == 'tag' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha,scope=nethack
+          cache-to: type=gha,mode=max,scope=nethack
+      - uses: docker/metadata-action@v4
+        id: meta_x11
+        with:
+          images: |
+            ${{ github.repository_owner }}/nethack-x11
+            ghcr.io/${{ github.repository_owner }}/nethack-x11
+          flavor: |
+            latest=true
+          tags: |
+            type=semver,pattern={{version}}
+      - uses: docker/build-push-action@v3
+        with:
+          context: x11
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.ref_type == 'tag' }}
+          tags: ${{ steps.meta_x11.outputs.tags }}
+          labels: ${{ steps.meta_x11.outputs.labels }}
+          cache-from: type=gha,scope=x11
+          cache-to: type=gha,mode=max,scope=x11