Add Gitea action for CI

.drone.yml

@@ -0,0 +1,9 @@
+kind: pipeline
+name: default
+
+steps:
+- name: test
+  image: ruby
+  commands:
+  - bundle install --jobs=3 --retry=3
+  - rake test

.gitea/workflows/ruby.yml

@@ -0,0 +1,33 @@
+name: Tests
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ['2.7', '3.0', '3.1']
+        redis-version: [6, 7]
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby-version }}
+        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
+    - name: Start Redis
+      uses: supercharge/redis-github-action@1.4.0
+      with:
+        redis-version: ${{ matrix.redis-version }}
+    - name: Configure
+      run: cp config.yml.erb.example config.yml.erb
+    - name: Run tests
+      run: bundle exec rake test