If your project stays as you describe it, REST isn't crucial. Given that you're using Rails, though, it's just as easy to do it as not do it, as idiomatic Rail

If your project stays as you describe it, REST isn't crucial. Given that you're using Rails, though, it's just as easy to do it as not do it, as idiomatic Rails automatically enforces that architecture and gives you API support "for free." Why fight against the framework?