Use GitHub action CI

.github/workflows/ruby.yml

@@ -0,0 +1,20 @@
+name: Ruby
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up Ruby 2.6
+      uses: actions/setup-ruby@v1
+      with:
+        ruby-version: 2.6.x
+    - name: Build and test with Rake
+      run: |
+        gem install bundler
+        bundle install --jobs 4 --retry 3
+        make test

Makefile

@@ -2,4 +2,7 @@
 install:
 	gem build json-api-vanilla.gemspec && gem install ./json-api-vanilla-*.gem
 
-.PHONY: install
+test:
+	rspec
+
+.PHONY: install test