ci: add a downstream tailwindcss-rails integration test

Author: flavorjones

.github/workflows/downstream.yml

@@ -25,9 +25,13 @@ jobs:
       matrix:
         include:
           - url: https://github.com/rails/tailwindcss-rails
-            name: tailwindcss-rails
+            name: rails-unit
             command: "bin/test"
             ruby: "3.3"
+          - url: https://github.com/rails/tailwindcss-rails
+            name: rails-integration
+            command: "test/integration/user_journey_test.sh"
+            ruby: "3.3"
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -41,7 +45,4 @@ jobs:
       - name: ${{matrix.name}} test suite
         working-directory: ${{matrix.name}}
         run: |
-          bundle remove tailwindcss-ruby || true
-          bundle add tailwindcss-ruby --path=".."
-          bundle install --local || bundle install
-          ${{matrix.command}}
+          TAILWINDCSSOPTS='--path=".."' ${{matrix.command}}