App based Rails site

I plan to make an app based rails site. The rails webapplication should only have authentication and the rest of the functionality are "apps". The basic idea is that users in the future could develop their own functions.

What is the best soulti开发者_开发问答on for this? Should i write my apps as a plugin or gem? Point me in right direction, thanks.

engines

ps - whilst the railscast is rails2.3, you can find your own way to more modern practices from there - rails_admin is a good gem which is written as an engine and does some of the stuff you probably want your code to do - have a look inside it's source for more info and google "rails 3" & "engines" for more info, i'm not so clued up on it myself