Add continuous integration with github actions (#53)

* create continuous integration for PHP test

* add docker test for continuous integration

.github/workflows/ci.yml

@@ -0,0 +1,31 @@
+name: continuous integration
+on:
+  pull_request:
+  push: { branches: master }
+jobs:
+  php_test:
+    name: PHP Test
+    runs-on: ${{ matrix.operating-system }}
+    strategy:
+      matrix:
+        operating-system: ['ubuntu-latest', 'windows-latest', 'macos-latest']
+        php-versions: ['7.4', '8.0', '8.1']
+    steps:
+    - name: Setup PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: ${{ matrix.php-versions }}
+        extensions: mbstring, intl
+        ini-values: post_max_size=256M, max_execution_time=180
+        coverage: xdebug
+        tools: php-cs-fixer
+  docker_test:
+    name: Build Docker Image Test
+    runs-on: ubuntu-latest
+    env:
+      COMPOSE_FILE: docker-compose.yaml
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Build docker images
+      run: docker-compose build