Add GitHub tests workflow

.github/workflows/tests.yml

@@ -0,0 +1,28 @@
+name: Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ ubuntu-latest, macos-latest, windows-latest ]
+        ruby: [ 3.3.0, jruby-9.4.5.0 ]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+    - name: Install dependencies
+      run: |
+        gem update --system
+        gem install bundler
+        bundle install --jobs 4 --retry 3
+    - name: Run Tests
+      run: rspec

.gitignore

@@ -1,2 +1,3 @@
 Gemfile.lock
 pkg/
+.tool-versions

README.md

@@ -1,4 +1,4 @@
-# Stroop [![[version]](https://badge.fury.io/rb/stroop.svg)](http://badge.fury.io/rb/stroop)  [![[travis]](https://travis-ci.org/paulgoetze/stroop.png)](https://travis-ci.org/paulgoetze/stroop)
+# Stroop [![[version]](https://badge.fury.io/rb/stroop.svg)](http://badge.fury.io/rb/stroop)  [![Build Status](https://github.com/paulgoetze/stroop/workflows/Tests/badge.svg)](https://github.com/paulgoetze/stroop/workflows/Tests/badge.svg)
 
 Stroop is a tiny CLI for printing Stroop tests in order to experience the psychological [Stroop effect](https://en.wikipedia.org/wiki/Stroop_effect).
 
@@ -44,8 +44,8 @@ For each print out you will find the random seed that was used to generate the c
 You can also pass a seed by using the `--seed` or `-s` option:
 
 ```bash
-$ stroop neutral --seed=1234 
-$ stroop congruent -s 1234 
+$ stroop neutral --seed=1234
+$ stroop congruent -s 1234
 $ stroop incongruent -s 1234
 ```