Add usage and build workflow

Author: petebachant

.github/workflows/publish-ghcr.yml

@@ -0,0 +1,53 @@
+name: Build and publish to GHCR
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - "v*"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=ref,event=branch
+            type=ref,event=tag
+            type=sha
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          platforms: linux/amd64,linux/arm64
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

README.md

@@ -3,3 +3,23 @@
 A Docker image that includes TinyTeX and latexmk.
 
 Based on https://github.com/carteakey/tinytex-docker.
+
+## Run the image locally
+
+Example command to:
+
+- Mount your current local project directory into the container
+- Mount a local TinyTeX cache directory so auto-installed TeX packages persist across runs
+
+```sh
+mkdir -p "$HOME/.cache/tinytex"
+
+docker run --rm -it \
+	-v "$PWD":/work \
+	-v "$HOME/.cache/tinytex":/root/.TinyTeX \
+	-w /work \
+	ghcr.io/calkit/tinytex-latexmk-docker:latest \
+	latexmk -pdf main.tex
+```
+
+Change `main.tex` to your document entrypoint.