Replace size with pagination (#59)

diff --git a/event.graphqls b/event.graphqls
index 5db400b..5526d83 100644
--- a/event.graphqls
+++ b/event.graphqls
@@ -60,7 +60,7 @@
     type: EventType
     time: Duration
     order: Order
-    size: Int
+    paging: Pagination!
 }
 
 extend type Query {