Rails Bad Request Bad Uri Due to Curly Brackets

Question

I need my url to allow curly brackets. Like so

http://localhost:3000/?target={target_id}

The reason for this is that the {target_id} param will be replaced later by a third party site. I will not read that parameter I just need the site to load when the url looks this way.

currently I get this messege

Bad Request

Bad URI '?target={target_id}`

How do I get WeBrick to ignore the curly brackets in the url and display the site?