It is possible to implement non-relational database (without SQL) to store data on Rails.
The definition of NoSql
Heroku's cloud support for NoSql and why it matters?
Article that apparently got Rubyists notice about NoSql
And get started to implementing NoSql
1) Install MongoDB
2) Setup MongoDB for Rails 3
3) Examples and explanations by Ryan Bates
Railscasts MongoDB and MongoMapper4) More info about MongoMapper
5) Thinking of using Heroku as your host?
There is also a cloud host for MongoDb, MongoHQ