Add GithubAction config

.github/workflows/ci.yml

@@ -0,0 +1,56 @@
+---
+name: CI
+
+on:
+  push:
+    branches:
+      - '**'
+  pull_request:
+    branches:
+      - '**'
+
+jobs:
+  rspec:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '3.3'
+          - '3.2'
+          - '3.1'
+          - '3.0'
+          - 'head'
+          - jruby
+          - jruby-head
+          - truffleruby
+          - truffleruby-head
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+
+      - name: Update bundler
+        env:
+          RUBY_VERSION: ${{ matrix.ruby }}
+        run: |
+          case ${RUBY_VERSION} in
+            truffleruby|truffleruby-head)
+              gem install bundler -v 2.5.18
+            ;;
+
+            *)
+              gem update --system
+            ;;
+          esac
+
+          bundle install
+
+      - name: RSpec
+        run: bin/rspec