exe/hrw in hrw-0.3.3 vs exe/hrw in hrw-0.3.4

@@ -23,9 +23,14 @@
     exit(1)
   end
 end
 
 scanner = Hrw::Detector.detect
+if scanner.nil?
+  puts '[-] can not detect package manager, skip'
+  exit(0)
+end
+
 specs = scanner.scan
 
 api = Hrw::API.new(options.url)
 hash = api.submit(specs, scanner.package_manager)
 result = api.retrieve(hash)