fix syntax error

app/logical/popular_search_service.rb

@@ -7,7 +7,7 @@ class PopularSearchService
     @scale = scale
   end
 
-  def each_search(&block, limit = 100)
+  def each_search(limit = 100, &block)
     fetch_data.scan(/(.+?) (\d+)\.0\n/).slice(0, limit).each(&block)
   end