We actually recommend exactly this to many of our customers. Unless the marketing homepage needs a lot of dynamic app-database driven content we usually recomme

We actually recommend exactly this to many of our customers. Unless the marketing homepage needs a lot of dynamic app-database driven content we usually recommend installing wordpress on www.domain.com and rails app on domain.com. when user is not logged-in, domain.com redirects to www.domain.com. this setup saves a lot of time on static pages management and adds quite a bit of marketing power.