feat(auth): implement user authentication system

backend/node_modules/@babel/plugin-transform-optional-chaining/README.md

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+# @babel/plugin-transform-optional-chaining
+
+> Transform optional chaining operators into a series of nil checks
+
+See our website [@babel/plugin-transform-optional-chaining](https://babeljs.io/docs/babel-plugin-transform-optional-chaining) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-transform-optional-chaining
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-transform-optional-chaining --dev
+```