Adding back CI file and adding CI file to .fernignore to stop accidental deletion

Author: fern-support

.fernignore

@@ -5,4 +5,5 @@ Rakefile
 .rubocop.yml
 square.gemspec
 .gitignore
-test/
+test/
+.github/workflows

.github/workflows/ci.yml

@@ -0,0 +1,130 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+# Cancel previous workflows on previous push
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
+# Global environment variables
+env:
+  RUBY_VERSION: '3.3'
+  BUNDLER_VERSION: '2.7'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ['3.2', '3.3', '3.4']
+        bundler-version: ${{ env.BUNDLER_VERSION }}
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-version: ${{ matrix.bundler-version }}
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: |
+          bundle install
+
+      - name: Build gem
+        run: |
+          bundle exec rake build
+
+      - name: Run tests
+        run: |
+          bundle exec rake test
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ env.RUBY_VERSION }}
+          bundler-version: ${{ env.BUNDLER_VERSION }}
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: |
+          bundle install
+
+      - name: Run RuboCop with auto-correct
+        run: |
+          bundle exec rake rubocop:autocorrect
+
+      # TODO: Uncomment this when we have a way a fix for all RuboCop violations
+      # - name: Check for RuboCop violations
+      #   run: |
+      #     bundle exec rubocop --fail-level W
+
+      - name: Ensure no changes to git-tracked files
+        run: git --no-pager diff --exit-code
+
+  security:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ env.RUBY_VERSION }}
+          bundler-version: ${{ env.BUNDLER_VERSION }}
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: |
+          bundle install
+
+      - name: Run bundle audit
+        run: |
+          bundle exec bundle audit check --update
+
+  gem-publish:
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main' || github.ref == 'refs/heads/master'
+    needs: [test, lint, security]
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ env.RUBY_VERSION }}
+          bundler-version: ${{ env.BUNDLER_VERSION }}
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: |
+          bundle install
+
+      - name: Build gem
+        run: |
+          bundle exec rake build
+
+      # TODO: Uncomment this when we are ready to publish to RubyGems
+      # - name: Publish to RubyGems
+      #   run: |
+      #     gem push pkg/*.gem
+      #   env:
+      #     RUBYGEMS_API_KEY: ${{ secrets.RUBYGEMS_API_KEY }}