What does it mean and how can I fix it:
pod install/Library/Ruby/Site/2.0.0/rubygems.rb:250:in `find_spec_for_exe': can't find gem cocoapods (>= 0.a) (Gem::GemNotFoundException)from /Library/Ruby/Site/2.0.0/rubygems.rb:278:in `activate_bin_path'from /usr/local/bin/pod:22:in `<main>'
