Developer/Designer needed to develop a Seating planner for a Ruby on rails application

We need a skilled front end designer to develop a seating planner for an existing rails application. The seating planner will include set shapes (table types) which the users can drag across a canvas and add individuals to each seat. The backend is ruby on rails. There are 2 options - You can either build it from scratch or we have a prototype in backbone.js which was developed for another app but can be integrated into this. Please apply only if you are well knowledgeable with rails , jquery , backbone and Git. Please also show examples of your work.