root@support:/home/rt-4.2.0# gem install passenger
Building native extensions.  This could take a while...
Successfully installed passenger-4.0.21
1 gem installed
Installing ri documentation for passenger-4.0.21...
Building YARD (yri) index for passenger-4.0.21...
ERROR:  While executing gem ... (NoMethodError)
    undefined method `map' for Gem::Specification:Class