Rails development caching indicator for zsh with POWERLEVEL9K

rails_cache_enabled.sh

# define a function that checking `caching-dev.txt` exists in tmp/
rails_cache_enabled(){
  if [[ -e tmp/caching-dev.txt ]]; then
    echo -n "\ue00a Caching "
  fi
}

# create a custom prompt theme element
POWERLEVEL9K_CUSTOM_RAILS_CACHE_ENABLED="rails_cache_enabled"
POWERLEVEL9K_CUSTOM_RAILS_CACHE_ENABLED_BACKGROUND=154
POWERLEVEL9K_CUSTOM_RAILS_CACHE_ENABLED_FOREGROUND=208

# then add that to left or right prompt elements
# e.g. POWERLEVEL9K_RIGHT_PROMPT_ELEMENTS=(custom_git_last_commit_time rbenv custom_rails_cache_enabled time_joined)