add github action and mention schema.sql in readme

Author: masflam

.github/workflows/build-publish.yaml

@@ -0,0 +1,50 @@
+name: Build and Publish Docker Image to GHCR
+
+on:
+  release:
+    types:
+      - published
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    
+    permissions:
+      contents: read
+      packages: write
+      id-token: write
+    
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      
+      # Extract metadata for Docker image
+      - name: Extract metadata for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
+      
+      # Build and push Docker image
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

README.md

@@ -65,3 +65,6 @@ docker compose down
 ```
 For more information, see the [Docker Compose docs](https://docs.docker.com/compose/).
 
+Note that this compose file mounts `./schema.sql` as a volume to the postgres container, which is
+the file executed on the container's first start, to create the `tipjars` table in the database.
+