Add Github actions so CI runs

.github/workflows/ci.yml

@@ -0,0 +1,52 @@
+name: "CI"
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "master"
+  schedule:
+    - cron: "42 3 * * *"
+
+jobs:
+  phpunit:
+    name: "PHPUnit"
+    runs-on: "ubuntu-20.04"
+
+    strategy:
+      matrix:
+        php-version:
+          - "5.4"
+          - "5.5"
+          - "5.6"
+          - "7.0"
+          - "7.1"
+          - "7.2"
+          - "7.3"
+          - "7.4"
+        dependencies:
+          - "highest"
+        include:
+          - dependencies: "lowest"
+            php-version: "5.4"
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2"
+        with:
+          fetch-depth: 2
+
+      - name: "Install PHP"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          php-version: "${{ matrix.php-version }}"
+          coverage: "none"
+          ini-values: "zend.assertions=1"
+
+      - name: "Install dependencies with Composer"
+        uses: "ramsey/composer-install@v1"
+        with:
+          dependency-versions: "${{ matrix.dependencies }}"
+
+      - name: "Run PHPUnit"
+        run: "vendor/bin/phpunit"

README.md

@@ -1,6 +1,6 @@
 # Ratchet
 
-[![Build Status](https://secure.travis-ci.org/ratchetphp/Ratchet.png?branch=master)](http://travis-ci.org/ratchetphp/Ratchet)
+[![GitHub Actions][GA Image]][GA Link]
 [![Autobahn Testsuite](https://img.shields.io/badge/Autobahn-passing-brightgreen.svg)](http://socketo.me/reports/ab/index.html)
 [![Latest Stable Version](https://poser.pugx.org/cboden/ratchet/v/stable.png)](https://packagist.org/packages/cboden/ratchet)
 
@@ -81,3 +81,7 @@ class MyChat implements MessageComponentInterface {
     conn.onmessage = function(e) { console.log(e.data); };
     conn.onopen = function(e) { conn.send('Hello Me!'); };
 ```
+
+[GA Image]: https://github.com/ratchetphp/Ratchet/workflows/CI/badge.svg
+
+[GA Link]: https://github.com/ratchetphp/Ratchet/actions?query=workflow%3A%22CI%22+branch%3Amaster