Include chrome buildpack to app_json

Co-authored-by: Michael Hale <[email protected]>

lib/generators/chromium/pdf/install/install_generator.rb

@@ -14,6 +14,15 @@ def create_pdf_job_templates
           copy_file 'app/jobs/generate_pdf_job.rb'
           copy_file 'config/initializers/good_job.rb'
         end
+
+        def include_chrome_buildpack_in_app_json
+          say(<<~SAY, :yellow)
+            N.B. app.json changes are not applied to existing heroku apps.
+            In the case where your app already exists make sure to manually add the buildpack by running the command:
+            `heroku buildpacks:add heroku-community/chrome-for-testing`
+          SAY
+          copy_file 'app.json'
+        end
       end
     end
   end

lib/generators/chromium/pdf/install/templates/app.json

@@ -0,0 +1,17 @@
+{
+    "buildpacks": [
+      {
+        "url":"heroku-community/chrome-for-testing"
+      },
+      {
+        "url":"heroku/metrics"
+      },
+      {
+        "url": "heroku/nodejs"
+      },
+      {
+        "url": "heroku/ruby"
+      }
+    ]
+  }
+

test/generators/install_generator_test.rb

@@ -18,4 +18,9 @@ class InstallGeneratorTest < Rails::Generators::TestCase
     run_generator
     assert_file 'config/initializers/good_job.rb'
   end
+
+  test 'app.json is created' do
+    run_generator
+    assert_file 'app.json'
+  end
 end