Build Docker images with GitHub actions

.github/workflows/build.yml

@@ -20,4 +20,25 @@ jobs:
       - run: poetry install
       - run: poetry run pytest
         env:
-          TEST_WEBHOOK_URL: ${{ secrets.TEST_WEBHOOK_URL }}
+          TEST_WEBHOOK_URL: ${{ secrets.TEST_WEBHOOK_URL }}
+      - name: Login to GitHub Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/thelovinator1/discord-rss-bot
+          flavor: latest=${{ github.ref == 'refs/heads/master' }}
+      - name: Build and push Docker image
+        id: build-and-push
+        uses: docker/build-push-action@v3
+        with:
+          context: .
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}