docs: add example section

README.md

@@ -50,6 +50,53 @@ then generate PHP code with command:
 ./vendor/bin/x-graphql-codegen x-graphql:codegen:generate
 ```
 
+Example
+-------
+
+Add `x-graphql/http-schema` package for executing schema over http:
+
+```shell
+composer require x-graphql/http-schema
+```
+
+Init config file:
+
+```shell
+./vendor/bin/x-graphql-codegen x-graphql:codegen:init-config
+```
+
+Add `example.graphql` to your current working directory with content:
+
+```graphql
+query getCountries {
+    countries {
+        name
+    }
+}
+```
+
+Run command to generate PHP code:
+
+```shell
+./vendor/bin/x-graphql-codegen x-graphql:codegen:generate
+```
+
+Use generated query class:
+
+```php
+<?php
+
+require __DIR__ . '/vendor/autoload.php';
+
+$delegator = new \XGraphQL\HttpSchema\HttpDelegator('https://countries.trevorblades.com/');
+$schema = \XGraphQL\HttpSchema\HttpSchemaFactory::createFromIntrospectionQuery($delegator);
+$query = new \App\GraphQL\Codegen\GraphQLQuery($schema);
+
+$result = $query->getCountries();
+
+var_dump($result->toArray());
+```
+
 Credits
 -------