setup pushing to rubygems

.github/workflows/ci.yaml

@@ -51,3 +51,32 @@ jobs:
         run: bundle install
       - name: Run tests
         run: bin/rspec
+
+  release:
+    name: Publish to RubyGems
+    runs-on: ubuntu-latest
+    needs: [release-please, test, lint]
+    if: ${{ needs.release-please.outputs.release_created }}
+    steps:
+      - uses: actions/checkout@master
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.2
+
+      - name: Build Gem
+        run: gem build *.gemspec
+
+      - name: Setup credentials
+        run: |
+          mkdir -p $HOME/.gem
+          touch $HOME/.gem/credentials
+          chmod 0600 $HOME/.gem/credentials
+          printf -- "---\n:rubygems_api_key: ${RUBYGEMS_API_KEY}\n" > $HOME/.gem/credentials
+        env:
+          RUBYGEMS_API_KEY: ${{secrets.KRYSTAL_RUBYGEMS_API_KEY}}
+
+      - name: Publish to RubyGems
+        run: |
+          gem push *.gem