Integrating Homebrew Into Ruby On Rails Project Setup

Let's integrate Homebrew into our Ruby on Rails Project local set up.
There is a convention for Ruby on Rails projects to use bin/setup to set up and install/update required dependencies. But by default, it does not include system dependencies. 
We are going to use the Homebrew Bundle tool for this.
First, we need to have a Brewfile with:

# Redis - For ActionCable support (and Sidekiq, caching, etc.)
brew "redis"
# PostgreSQL - brew install postgresql
brew "postgresql"
# Overmind (requires tmux)
brew "tmux"
brew "overmind"
# Imagemagick or libvips - for processing images (avatars, file upload...