Error ->
dlopen(/Users/vivek/.rvm/gems/ruby-1.9.3-p327/gems/rmagick-2.13.1/lib/RMagick2.bundle, 9): Library not loaded: /usr/local/lib/libjpeg.8.dylib Referenced from: /usr/local/opt/imagemagick/lib/libMagickCore.5.dylib Reason: Incompatible library version: libMagickCore.5.dylib requires version 13.0.0 or later, but libjpeg.8.dylib provides version 12.0.0 - /Users/vivek/.rvm/gems/ruby-1.9.3-p327/gems/rmagick-2.13.1/lib/RMagick2.bundle
Step1 : Update XCode. Get the latest one Xcode 4.6 Mountain Lion does not come with ruby headers installed before hand, so you need to do this manually from XCode. Go to Xcode Preferences/Downloads.
Install Command Line Tools