Add Dockerfile and docker build github action

Adds support for container builds. Github action will automatically
build images on master branches and on releases and push them to the
github container registry.

.github/workflows/docker-build.yaml

@@ -0,0 +1,51 @@
+name: docker-build
+
+on:
+  push:
+    branches:
+      - "master*"
+  release:
+    types: [published]
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  docker-build:
+    name: Build and deploy container images
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@v2
+      - name: Export git tag
+        uses: tenhaus/get-release-or-tag@v2
+        id: tag
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            # branch event
+            type=ref,event=branch
+            # tag event
+            type=ref,event=tag
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Login to ghcr.io
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build image
+        uses: docker/build-push-action@v2
+        with:
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: TODOCHECK_VERSION=${{ steps.tag.outputs.tag }}

Dockerfile

@@ -0,0 +1,12 @@
+FROM golang:1.18.5-alpine3.16 AS build
+ARG TODOCHECK_VERSION=custom_version
+
+ADD . /usr/src/todocheck
+WORKDIR /usr/src/todocheck 
+
+# Build
+RUN go build -ldflags "-X main.version=$TODOCHECK_VERSION"
+
+FROM alpine:3.16
+COPY --from=build /usr/src/todocheck/todocheck /usr/local/bin/todocheck
+ENTRYPOINT ["/usr/local/bin/todocheck"]

README.md

@@ -81,6 +81,16 @@ Optionally verify the `sha256` checksum:
 Place the binary in a folder, shined upon by your `$PATH`.
  * For macos & linux, that's typically `/usr/local/bin/`
 
+## Using a Container
+Alternatively to installing the todocheck binary on your system you may use a prebuilt container image from the GitHub container registry, e.g.:
+
+```bash
+docker run -it -v /path/to/project:/project -e TODOCHECK_AUTH_TOKEN=your_token ghcr.io/preslavmihaylov/todocheck --basepath /project
+```
+
+For a complete list of container tags visit the [Packages section](https://github.com/preslavmihaylov/todocheck/pkgs/container/todocheck) on the GitHub project page.
+For a complete list of `docker run` options visit the [Docker documentation](https://docs.docker.com/engine/reference/commandline/run/).
+
 # Quickstart
 First, you need to configure `todocheck`'s integration with your issue tracker.
 This is done by creating a `.todocheck.yaml` file in the root of your project.