add graphql endpoint

app/graphql/x_stake_schema.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+class XStakeSchema < GraphQL::Schema
+  mutation(Types::MutationType)
+  query(Types::QueryType)
+
+  def self.resolve_type(abstract_type, obj, ctx)
+    raise(GraphQL::RequiredImplementationMissingError)
+  end
+
+  def self.id_from_object(object, type_definition, query_ctx)
+    GraphQL::Schema::UniqueWithinType.encode(type_definition.name, object.id)
+  end
+
+  def self.object_from_id(id, query_ctx)
+    type_name, item_id = GraphQL::Schema::UniqueWithinType.decode(id)
+    type_name.constantize.find(item_id)
+  end
+end