Adds CI with Actions

Author: Raffo

.github/workflows/ruby.yml

@@ -0,0 +1,20 @@
+name: CI
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up Ruby 2.5.7
+      uses: actions/setup-ruby@v1
+      with:
+        ruby-version: 2.5.7
+    - name: Build and test
+      run: |
+        gem install bundler:1.16.1
+        bundle install
+        bin/rspec