I'm somewhat new to the Rails asset pipeline so I might be doing something wrong. I'm trying to use Active Admin for my backend and twitter bootstrap css for my front end application.
I added the bootstrap.css to /app/assets/stylesheets then also added:
//= require bootstrap
Have you watched the RailsCasts video on using ActiveAdmin? In the video, Ryan shows you how to prevent the ActiveAdmin CSS from stepping on your main app CSS.
Moving info from Video into answer
In the application.css you remove:
*= require_tree .
For rails 4, Jiten K suggests adding this to
config.assets.precompile += ['active_admin.css']
However one of the comments on that SO answer says this is not needed. I have not needed it so far.