docs: add README

Author: vuongxuongminh

README.md

@@ -0,0 +1,45 @@
+Schema Cache
+============
+
+Save and lazy load [GraphQL Schema](https://webonyx.github.io/graphql-php/schema-definition/) from PSR-16 cache.
+
+![unit tests](https://github.com/x-graphql/schema-cache/actions/workflows/unit_tests.yml/badge.svg)
+[![codecov](https://codecov.io/gh/x-graphql/schema-cache/graph/badge.svg?token=c1xCJsFvIs)](https://codecov.io/gh/x-graphql/schema-cache)
+
+
+Getting Started
+---------------
+
+Install this package via [Composer](https://getcomposer.org)
+
+```shell
+composer require x-graphql/schema-cache symfony/cache
+```
+
+Usages
+------
+
+Create an instance of `XGraphQL\SchemaCache\SchemaCache` with PSR-16 to save and load:
+
+```php
+use Symfony\Component\Cache\Adapter\ArrayAdapter;
+use Symfony\Component\Cache\Psr16Cache;
+use XGraphQL\SchemaCache\SchemaCache;
+
+$psr16 = new Psr16Cache(new ArrayAdapter());
+$schemaCache = new SchemaCache($psr16);
+
+$schemaCache->save(/* $schema */);
+
+/// Lazy to load on another http requests
+
+$schemaFromCache = $schemaCache->load();
+```
+> [!NOTE]
+> This package not support to decorate type after load schema from cache,
+> you need to add type resolvers before execute schema.
+
+Credits
+-------
+
+Created by [Minh Vuong](https://github.com/vuongxuongminh)