Your package rubygem-simple-navigation failed to build from source in current rawhide. http://koji.fedoraproject.org/koji/taskinfo?taskID=5772133 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_20_Mass_Rebuild
http://koji.fedoraproject.org/koji/taskinfo?taskID=5818299 It just works. FTBFS was caused probably by RoR, which were broken ATM.