I installed ActiveAdmin successfully:
My gemfile code:
source \'https://rubygems.org\'
gem \'rails\', \'3.2.10\' # Bundle edge Rails instead:
I had the same issue and switched from WillPaginate to Kaminari for my app.
It is a simple change: paginate(page:1,per_page:10) becomes page(1).per(10)
I guess it depends how deeply willPaginate is enmeshed with your app.