Refactor link attribute generation on ProcedureSerializer

spec/serializers/procedure_serializer_spec.rb

@@ -0,0 +1,10 @@
+describe ProcedureSerializer do
+  describe '#attributes' do
+    subject { ProcedureSerializer.new(procedure).serializable_hash }
+    let(:procedure) { create(:procedure, :published) }
+
+    it {
+      is_expected.to include(link: "http://localhost:3000/commencer/#{procedure.path}")
+    }
+  end
+end