to show rvm in zsh prompt

zsh_rvm_prompt

# add the rvm_info_for_prompt into your prompt
# below is my full prompt
PS1='%{$fg[white]%}%n%{$fg[cyan]%}:%{$fg_no_bold[yellow]%}%3~%{$fg_no_bold[green]%}$(git_info_for_prompt)%{$fg_no_bold[magenta]%}$(rvm_info_for_prompt)%{$reset_color%}# '

# this tests for the presence of rvm 
# if its loaded, it'll add the prompt
function rvm_info_for_prompt {
  ruby_version=$(~/.rvm/bin/rvm-prompt)
  if [ -n "$ruby_version" ]; then
    echo "[$ruby_version]"
  fi
}