Rails vs rails-api

[opti]

Just summarise the conversation we've had in campfire:

I'm not sure, that we need to use the most of rails for this app. This application should be light enough, so something like Sinatra or rails-api is more suitable for our case.

@spectator:

but since most of us prefer rails (I guess) let's use lighter version of it (rails-api)... it's actually very focused for building APIs

Any suggestions?