This is how to check dependencies for local development. Save as setup/check into rails app.

check.sh

#!/usr/bin/env bash

function dependency {
  $2 > /dev/null 2>&1
  if [[ "$?" == "0" ]] ; then
    echo "$1 installed"
  else
    echo "To install $1: '$3'"
  fi 
}

#           name          |  command            | how to install
#          ---------------|---------------------|-------------------------------------
dependency "rbenv"         "rbenv --version"     "brew install rbenv ruby-build"
dependency "bundler"       "bundle -v"           "gem install bundler"
dependency "powder"        "powder -v"           "gem install powder"
dependency "postgresql"    "psql --version"      "brew install postgresql"
dependency "elasticsearch" "elasticsearch -h"    "brew install elasticsearch"

Example output:

rbenv installed
bundler installed
powder installed
postgresql installed
elasticsearch installed