setup github actions

Author: khiga8

.github/workflows/ci.yml

@@ -0,0 +1,39 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+    - name: Setup Ruby
+      uses: actions/setup-ruby@v1
+      with:
+        ruby-version: 3.0.x
+    - uses: actions/cache@v2
+      with:
+        path: vendor/bundle
+        key: gems-build-rails-main-ruby-2.7.x-${{ hashFiles('**/Gemfile.lock') }}
+    - name: Lint with Rubocop
+      run: |
+        gem install bundler:2.2.9
+        bundle config path vendor/bundle
+        bundle install --jobs 4 --retry 3
+        bundle exec rubocop
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby_version: ["2.6", "2.7", "3.0"]
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby_version }}
+    - name: Install dependencies
+      run: bundle install --jobs 4 --retry 3
+    - name: Run tests
+      run: bundle exec rake