GoogleOauth2.0 First implementation

First try for GoogleOauth2.0

express-server/node_modules/gcp-metadata/README.md

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+# gcp-metadata
+> Get the metadata from a Google Cloud Platform environment.
+
+[![NPM Version][npm-image]][npm-url]
+[![CircleCI][circleimg]][circle]
+[![codecov][codecov-image]][codecov-url]
+
+```sh
+$ npm install --save gcp-metadata
+```
+```js
+const gcpMetadata = require('gcp-metadata');
+```
+
+#### Check to see if the metadata server is available
+```js
+const isAvailable = await gcpMetadata.isAvailable();
+```
+
+#### Access all metadata
+```js
+const res = await gcpMetadata.instance();
+console.log(res.data); // ... All metadata properties
+```
+
+#### Access specific properties
+```js
+const res = await gcpMetadata.instance('hostname');
+console.log(res.data) // ...All metadata properties
+```
+
+#### Access specific properties with query parameters
+```js
+const res = await gcpMetadata.instance({
+  property: 'tags',
+  params: { alt: 'text' }
+});
+console.log(res.data) // ...Tags as newline-delimited list
+```
+
+[circle]: https://circleci.com/gh/stephenplusplus/gcp-metadata
+[circleimg]: https://circleci.com/gh/stephenplusplus/gcp-metadata.svg?style=shield
+[codecov-image]: https://codecov.io/gh/stephenplusplus/gcp-metadata/branch/master/graph/badge.svg
+[codecov-url]: https://codecov.io/gh/stephenplusplus/gcp-metadata
+[npm-image]: https://img.shields.io/npm/v/gcp-metadata.svg
+[npm-url]: https://www.npmjs.com/package/gcp-metadata