Added validator for crawl models.
Added validator for crawl models.

YongchaoShang/memex-explorer,memex-explorer/memex-explorer,YongchaoShang/memex-explorer,memex-explorer/memex-explorer,memex-explorer/memex-explorer,memex-explorer/memex-explorer,YongchaoShang/memex-explorer,YongchaoShang/memex-explorer