Memoize values that should not change

Author: n-rodriguez

lib/ajax-datatables-rails/datatable/column.rb

@@ -43,11 +43,11 @@ def table
       end
 
       def model
-        source.split('.').first.constantize
+        @model ||= source.split('.').first.constantize
       end
 
       def field
-        source.split('.').last.to_sym
+        @field ||= source.split('.').last.to_sym
       end
 
       def custom_field?