decrease container spin to once per test

spec/simple_spec.rb

@@ -49,15 +49,17 @@ RSpec.describe "Simple" do
     let(:name) { "clean_urls" }
 
     it "should drop the .html extension from URLs" do
-      response = app.get("/foo")
-      expect(response.code).to eq("200")
-      expect(response.body.chomp).to eq("foobar")
+      app.run do
+        response = app.get("/foo")
+        expect(response.code).to eq("200")
+        expect(response.body.chomp).to eq("foobar")
 
-      response = app.get("/bar")
-      expect(response.code).to eq("301")
-      response = app.get(response["Location"])
-      expect(response.code).to eq("200")
-      expect(response.body.chomp).to eq("bar")
+        response = app.get("/bar")
+        expect(response.code).to eq("301")
+        response = app.get(response["Location"])
+        expect(response.code).to eq("200")
+        expect(response.body.chomp).to eq("bar")
+      end
     end
   end