feat: Add github workflow

.github/workflows/main.yml

@@ -0,0 +1,34 @@
+name: Ruby CI
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Ruby ${{ matrix.ruby }}
+    strategy:
+      matrix:
+        ruby:
+          - '2.5.1'
+          - '2.6.5'
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+
+    - name: Install Bundler
+      run: gem install bundler -v 2.1.4
+
+    - name: Install dependencies
+      run: bundle install