Run tests in github actions

To set this up I more or less followed an example I found online[1]. I
decided to use the "alpine" postgres image as the author suggests to
make the container creation quicker. I opted for the latest postgres
15, as this matches my development environment (and, I hope,
production when we get there).

[1] https://boringrails.com/articles/building-a-rails-ci-pipeline-with-github-actions/

.github/workflows/ci.yml

@@ -0,0 +1,57 @@
+name: CI
+on: [push]
+
+jobs:
+  linters:
+    name: Linters
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Ruby and install gems
+        uses: ruby/setup-ruby@v1
+        with:
+          bundler-cache: true
+
+      - name: Run linters
+        run: |
+          bin/rake rubocop
+
+  tests:
+    name: Tests
+    runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres:15-alpine
+        env:
+          POSTGRES_USER: myapp
+          POSTGRES_DB: myapp_test
+          POSTGRES_PASSWORD: password
+        ports: ["5432:5432"]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Ruby and install gems
+        uses: ruby/setup-ruby@v1
+        with:
+          bundler-cache: true
+
+      - name: Setup test database
+        env:
+          RAILS_ENV: test
+          PGHOST: localhost
+          PGUSER: myapp
+          PGPASSWORD: password
+        run: |
+          bin/rails db:setup
+
+      - name: Run tests
+        env:
+          RAILS_ENV: test
+          PGHOST: localhost
+          PGUSER: myapp
+          PGPASSWORD: password
+        run: bin/rake test:all

Gemfile.lock

@@ -149,6 +149,8 @@ GEM
     nio4r (2.5.9)
     nokogiri (1.15.3-arm64-darwin)
       racc (~> 1.4)
+    nokogiri (1.15.3-x86_64-linux)
+      racc (~> 1.4)
     parallel (1.23.0)
     parser (3.2.2.3)
       ast (~> 2.4.1)
@@ -235,6 +237,8 @@ GEM
       railties (>= 6.0.0)
     tailwindcss-rails (2.0.30-arm64-darwin)
       railties (>= 6.0.0)
+    tailwindcss-rails (2.0.30-x86_64-linux)
+      railties (>= 6.0.0)
     thor (1.2.2)
     timeout (0.4.0)
     turbo-rails (1.4.0)
@@ -260,6 +264,7 @@ GEM
 
 PLATFORMS
   arm64-darwin-22
+  x86_64-linux
 
 DEPENDENCIES
   bootsnap