feat(ui): nightwatch task

packages/@vue/cli-plugin-e2e-nightwatch/ui.js

@@ -0,0 +1,18 @@
+module.exports = api => {
+  api.describeTask({
+    match: /vue-cli-service test:e2e/,
+    description: 'nightwatch.tasks.test.description',
+    link: 'https://github.com/vuejs/vue-cli/tree/dev/packages/%40vue/cli-plugin-e2e-nightwatch#injected-commands',
+    prompts: [
+      {
+        name: 'url',
+        type: 'input',
+        default: '',
+        description: 'nightwatch.tasks.test.url'
+      }
+    ],
+    onBeforeRun: ({ answers, args }) => {
+      if (answers.url) args.push('--url', answers.url)
+    }
+  })
+}

packages/@vue/cli/locales/en.json

@@ -453,5 +453,13 @@
         "url": "Run e2e tests against given url instead of auto-starting dev server"
       }
     }
+  },
+  "nightwatch": {
+    "tasks": {
+      "test": {
+        "description": "Run e2e tests with nightwatch",
+        "url": "Run e2e tests against given url instead of auto-starting dev server"
+      }
+    }
   }
 }