RailsBridge "bundle install --without production" Error - ruby-on-rails

Question

In step Step 2.2 (Prepare your rails app for deploying to Heroku) of RailsBridge, you are prompted to type this in the terminal:
bundle install --without production
Unfortunately, it is printing out an error reading "The system cannot find the path specified." It then proceeds to tell you that if you given this error to ask for a volunteer to help you edit the config/environments/production.rb. StackOverflow, you are my volunteer! Please help, you're my only hope.
Here is the code in "Gemfile":
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.5.2'
# Use sqlite3 as the database for Active Record
group :development, :test do
gem 'sqlite3'
end
group :production do
gem 'pg'
gem 'rails_12factor'
end
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use Unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
group :development, :test do
# Call 'byebug' anywhere in the code to stop execution and get a debugger console
gem 'byebug'
end
group :development do
# Access an IRB console on exception pages or by using <%= console %> in views
gem 'web-console', '~> 2.0'
end
# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
And here is the code in "production.rb":
Rails.application.configure do
# Settings specified here will take precedence over those in config/application.rb.
# Code is not reloaded between requests.
config.cache_classes = true
# Eager load code on boot. This eager loads most of Rails and
# your application in memory, allowing both threaded web servers
# and those relying on copy on write to perform better.
# Rake tasks automatically ignore this option for performance.
config.eager_load = true
# Full error reports are disabled and caching is turned on.
config.consider_all_requests_local = false
config.action_controller.perform_caching = true
# Enable Rack::Cache to put a simple HTTP cache in front of your application
# Add `rack-cache` to your Gemfile before enabling this.
# For large-scale production use, consider using a caching reverse proxy like
# NGINX, varnish or squid.
# config.action_dispatch.rack_cache = true
# Disable serving static files from the `/public` folder by default since
# Apache or NGINX already handles this.
config.serve_static_files = ENV['RAILS_SERVE_STATIC_FILES'].present?
# Compress JavaScripts and CSS.
config.assets.js_compressor = :uglifier
# config.assets.css_compressor = :sass
# Do not fallback to assets pipeline if a precompiled asset is missed.
config.assets.compile = false
# Asset digests allow you to set far-future HTTP expiration dates on all assets,
# yet still be able to expire them through the digest params.
config.assets.digest = true
# `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb
# Specifies the header that your server uses for sending files.
# config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
# config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
# Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
# config.force_ssl = true
# Use the lowest log level to ensure availability of diagnostic information
# when problems arise.
config.log_level = :debug
# Prepend all log lines with the following tags.
# config.log_tags = [ :subdomain, :uuid ]
# Use a different logger for distributed setups.
# config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)
# Use a different cache store in production.
# config.cache_store = :mem_cache_store
# Enable serving of images, stylesheets, and JavaScripts from an asset server.
# config.action_controller.asset_host = 'http://assets.example.com'
# Ignore bad email addresses and do not raise email delivery errors.
# Set this to true and configure the email server for immediate delivery to raise delivery errors.
# config.action_mailer.raise_delivery_errors = false
# Enable locale fallbacks for I18n (makes lookups for any locale fall back to
# the I18n.default_locale when a translation cannot be found).
config.i18n.fallbacks = true
# Send deprecation notices to registered listeners.
config.active_support.deprecation = :notify
# Use default logging formatter so that PID and timestamp are not suppressed.
config.log_formatter = ::Logger::Formatter.new
# Do not dump schema after migrations.
config.active_record.dump_schema_after_migration = false
end
In advance, thanks to whoever decides to help out!

Answer 1

Missing the
gem 'puma', '~> 3.0' line