Run rspec and standardrb on push

Author: aelkiss

.github/workflows/tests.yml

@@ -0,0 +1,22 @@
+name: Run Tests
+
+on: push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Ruby ${{ matrix.ruby }}
+    strategy:
+      matrix:
+        ruby: [2.7, 3.0, 3.1, 3.2]
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
+    - name: Run linter for Ruby
+      run: bundle exec standardrb
+    - name: Run tests
+      run: bundle exec rspec

README.md

@@ -1,5 +1,7 @@
 # HathiTrust::Pairtree
 
+[![Tests](https://github.com/hathitrust/ht-pairtree/actions/workflows/tests.yml/badge.svg)](https://github.com/hathitrust/ht-pairtree/actions/workflows/tests.yml)
+
 Deal with a [Pairtree](https://github.com/mlibrary/pairtree) given an HTID.
 
 Allows both reading and creation of the underlying pairtree directories