Merge pull request #36 from lsst-sqre/tickets/DM-41850

DM-41850: Add workflow to build docker image

.github/workflows/ci.yaml

@@ -0,0 +1,28 @@
+name: CI
+
+"on":
+  merge_group: {}
+  pull_request: {}
+  push:
+    tags:
+      - "*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    # (optional) only build on tags or ticket branches
+    if: >
+      startsWith(github.ref, 'refs/tags/')
+      || startsWith(github.head_ref, 'tickets/')
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: lsst-sqre/build-and-push-to-ghcr@v1
+        id: build
+        with:
+          image: ${{ github.repository }} # e.g. lsst-sqre/safirdemo
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+
+      - run: echo Pushed ghcr.io/${{ github.repository }}:${{ steps.build.outputs.tag }}