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GitHub User: vita251
I had the same problem, then I installed the following gems and it worked fine! (Rails 3.2.8)
After adding the gem 'devise_rpx_connectable', I ran into the same error: 'require': cannot load such file -- devise/schema (LoadError). I got rid of the error by deleting the contents of the corresponding schema.rb and the migration command seemed to work again.
It seems that with the newer version (> 2.1) of devise, the contents of this file aren't necessary. Hope this solves other peoples issues, especially if they decide to update the devise gem and continue to use devise_rpx_connectable like I did.