Added offset argument to default args list (#270)

Author: gitsebs

src/defaultListArgs.js

@@ -12,6 +12,9 @@ module.exports = function () {
     where: {
       type: JSONType,
       description: 'A JSON object conforming the the shape specified in http://docs.sequelizejs.com/en/latest/docs/querying/'
+    },
+    offset: {
+      type: GraphQLInt
     }
   };