These are the few steps I ran to completely remove RVM and install rbenv:
To remove pretty much everything:
$ rvm implode
and to tidy up:
$ vim .zshrc # and remove the changes to PATH
Install:
$ brew update
$ brew install rbenv ruby-build
then configure:
vim .zshrc
and add:
export RBENV_ROOT=/usr/local/var/rbenv
if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi
That's it!