Extract default stages into something that will be created together with a new Workflow in the model

test/controllers/workflows_controller_test.rb

@@ -0,0 +1,19 @@
+require "test_helper"
+
+class WorkflowsControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    sign_in_as :kevin
+  end
+
+  test "index" do
+    get workflows_path
+    assert_in_body workflows(:on_call).name
+  end
+
+  test "create" do
+    assert_difference -> { Workflow.count }, +1 do
+      post workflows_path, params: { workflow: { name: "My new workflow!" } }
+      assert_redirected_to workflows_path
+    end
+  end
+end