At least one schema should be declared

[martijn-moveyou]

I followed the installation steps in the readme file. Everything installs great.

In the config/types/ directory I start a greeting type with the filename Greeting.types.yaml with the following content:

Greeting:
  type: Object
  config:
    resolveField: '@=resolver("App\\GraphQL\\Resolver\\GreetingResolver", [info, value])'
    fields:
      text:
        type: String!
        args:
          name:
            type: String

I create a file with the name GreetingResolver in the App\GraphQL\Resolver\ package that des the resolve. It looks like this:

Class GreetingResolver implements QueryInterface
{
    public function __invoke(ResolveInfo $info, $value)
    {
        $method = $info->fieldName;

        if(!isset($info->variableValues['name'])) {
            return $this->$method($value);
        } else {
            return $this->$method($value, $info->variableValues['name']);
        }
    }
    
    public function resolve() :TypesGreetingEntity
    {
         return new GreetingEntity('Hi, ');
    }

    public function text(GreetingEntity $greetingEntity, string $name = '') :string
    {
        return $greetingEntity->greeting . ' ' . $name . '!';
    }
    
}

In the graphql/types/Query.types.yaml file I add the Queries:

Query:
  type: object
  config:
    fields:
      greeting:
        type: Greeting
        resolve: '@=resolver("App\\GraphQL\\Resolver\\GreetingResolver::resolve")'
        args:
          name:
            type: String

I then use postman to do a post call to http://localhost:8000/graphql/ and I then get the following error in my logs:

Uncaught PHP Exception RuntimeException: "At least one schema should be declare." at /var/www/vendor/overblog/graphql-bundle/src/Request/Executor.php line 82 {"exception":"[object] (RuntimeException(code: 0): At least one schema should be declare. at /var/www/vendor/overblog/graphql-bundle/src/Request/Executor.php:82)"} []

How do I define a schema? Is it needed?