feat(auth): implement user authentication system

backend/node_modules/lodash.once/README.md

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+# lodash.once v4.1.1
+
+The [lodash](https://lodash.com/) method `_.once` exported as a [Node.js](https://nodejs.org/) module.
+
+## Installation
+
+Using npm:
+```bash
+$ {sudo -H} npm i -g npm
+$ npm i --save lodash.once
+```
+
+In Node.js:
+```js
+var once = require('lodash.once');
+```
+
+See the [documentation](https://lodash.com/docs#once) or [package source](https://github.com/lodash/lodash/blob/4.1.1-npm-packages/lodash.once) for more details.