在Linux Mint中开始Ruby on Rails

This may sound very basic to many of you. I have just started a Ruby on Rails tutorial in Linux. I'm very new to the Linux OS. I have installed a rvm. But I am unable to install Rails. It's saying "cant load such file --zlib". And I can see two source files for Ruby. Not sure if I have two Ruby installed.This may sound very basic to many of you. I hav