Install Cocoapods in RVM

Make sure you're using RVM ruby

$rvm use
Using /Users/*****/.rvm/gems/ruby-2.4.1

Install Cocoapods by RVM

$rvmsudo gem install cocoapods

Check

$where pod
/Users/xwayne/.rvm/gems/ruby-2.4.1/bin/pod
/usr/local/bin/pod