database_connection.rb

#config/initializers/database_connection.rb
Rails.application.config.after_initialize do
  ActiveRecord::Base.connection_pool.disconnect!

  ActiveSupport.on_load(:active_record) do
    config = Rails.application.config.database_configuration[Rails.env]
    config['reaping_frequency'] = ENV['DB_REAP_FREQ'] || 10 # seconds
    config['pool']              = ENV['DB_POOL']      || 5
    ActiveRecord::Base.establish_connection(config)
  end
end

environment.rb

# Load the Rails application.
require File.expand_path('../application', __FILE__)

# Initialize the Rails application.
Glowcon::Application.initialize!

Log output

Fetching repository, done.
Counting objects: 33, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (24/24), done.
Writing objects: 100% (24/24), 2.37 KiB | 0 bytes/s, done.
Total 24 (delta 17), reused 0 (delta 0)

-----> Ruby app detected
-----> Compiling Ruby/Rails
-----> Using Ruby version: ruby-2.0.0
-----> Installing dependencies using Bundler version 1.5.2
       Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
       Fetching source index from http://rubygems.org/
       Fetching git://github.com/gregbell/active_admin.git
       Using rake (10.1.1)
       Using i18n (0.6.9)
       Using minitest (4.7.5)
       Using atomic (1.1.14)
       Using builder (3.1.4)
       Using tzinfo (0.3.38)
       Using erubis (2.7.0)
       Using mime-types (1.25.1)
       Using rack (1.5.2)
       Using polyglot (0.3.3)
       Using sass (3.2.13)
       Using thor (0.18.1)
       Using bcrypt-ruby (3.1.2)
       Using execjs (2.0.2)
       Using coffee-script-source (1.6.3)
       Using orm_adapter (0.5.0)
       Using activerecord-deprecated_finders (1.0.3)
       Using arel (4.0.1)
       Using bundler (1.5.2)
       Using hike (1.2.3)
       Using tilt (1.4.1)
       Using json (1.8.1)
       Using highline (1.6.20)
       Using uuidtools (2.1.4)
       Using mini_portile (0.5.2)
       Using net-ssh (2.7.0)
       Using unicode_utils (1.4.0)
       Using chunky_png (1.2.9)
       Using fssm (0.2.10)
       Using currencies (0.4.2)
       Using kgio (2.8.1)
       Using libv8 (3.16.14.3)
       Using newrelic_rpm (3.7.1.182)
       Using pg (0.17.1)
       Using pwdcalc (0.1.10)
       Using rails_serve_static_assets (0.0.2)
       Using rails_stdout_logging (0.0.3)
       Using raindrops (0.12.0)
       Using ref (1.0.5)
       Using state_machine (1.2.0)
       Using yui-compressor (0.12.0)
       Using thread_safe (0.1.3)
       Installing mono_logger (1.1.0)
       Using faker (1.2.0)
       Using treetop (1.4.15)
       Installing multi_json (1.8.4)
       Using rack-test (0.6.2)
       Using warden (1.2.3)
       Installing redis (3.0.6)
       Installing rufus-scheduler (2.0.24)
       Using coffee-script (2.2.0)
       Using haml (4.0.5)
       Installing vegas (0.1.11)
       Using uglifier (2.4.0)
       Using nokogiri (1.6.1)
       Using net-scp (1.1.2)
       Using net-sftp (2.1.2)
       Using net-ssh-gateway (1.2.0)
       Using carmen (1.0.0)
       Using countries (0.9.3)
       Using compass (0.12.2)
       Using rails_12factor (0.0.2)
       Installing rack-protection (1.5.2)
       Using therubyracer (0.12.0)
       Using mail (2.5.4)
       Using activesupport (4.0.2)
       Using sprockets (2.10.1)
       Installing redis-namespace (1.4.1)
       Installing bourbon (3.1.8)
       Using capistrano (2.15.5)
       Using compass-rails (1.1.3)
       Installing sinatra (1.4.4)
       Using actionpack (4.0.2)
       Using activemodel (4.0.2)
       Installing arbre (1.0.1)
       Using climate_control (0.0.3)
       Installing rdoc (4.1.1)
       Using actionmailer (4.0.2)
       Using railties (4.0.2)
       Installing aws-sdk (1.32.0)
       Installing resque (1.25.1)
       Installing has_scope (0.6.0.rc)
       Using sprockets-rails (2.0.1)
       Installing formtastic (2.3.0.rc2)
       Using active_model_serializers (0.8.1)
       Using activerecord (4.0.2)
       Using cocaine (0.5.3)
       Using coffee-rails (4.0.1)
       Using devise (3.2.2)
       Installing responders (1.0.0)
       Using jquery-rails (3.0.4)
       Using jquery-ui-rails (4.1.1)
       Installing kaminari (0.15.1)
       Using haml-rails (0.5.3)
       Using jquery-fileupload-rails (0.4.1)
       Using jquery-powertip-rails (1.1.0) from git://github.com/malagodia/jquery-powertip-rails.git (at master)
       Installing resque-scheduler (2.3.1)
       Using sass-rails (4.0.1)
       Using paperclip (3.5.2)
       Installing sdoc (0.4.0)
       Using rails (4.0.2)
       Using after_commit_action (0.1.3)
       Installing foundation-rails (5.0.3.1)
       Using jquery-datatables-rails (1.12.2)
       Using acts-as-taggable-on (3.0.1)
       Using carmen-rails (1.0.0)
       Using counter_culture (0.1.18)
       Installing polyamorous (0.6.4)
       Installing inherited_resources (1.4.1)
       Installing ransack (1.1.0)
       Using activeadmin (1.0.0.pre) from git://github.com/gregbell/active_admin.git (at master)
       Installing unicorn (4.8.0)
       Your bundle is complete!
       Gems in the groups development and test were not installed.
       It was installed into ./vendor/bundle
       Post-install message from rdoc:
       Depending on your version of ruby, you may need to install ruby rdoc/ri data:
       <= 1.8.6 : unsupported
       = 1.8.7 : gem install rdoc-data; rdoc-data --install
       = 1.9.1 : gem install rdoc-data; rdoc-data --install
       >= 1.9.2 : nothing to do! Yay!
       Bundle completed (43.51s)
       Cleaning up the bundler cache.
       Removing bundler (1.3.2)
       Removing aws-sdk (1.31.3)
       Removing unicorn (4.7.0)
       Removing multi_json (1.8.2)
       Removing kaminari (0.15.0)
       Removing foundation-rails (5.0.2.0)
       Removing rdoc (3.12.2)
       Removing sdoc (0.3.20)
-----> Writing config/database.yml to read from DATABASE_URL
-----> Preparing app for Rails asset pipeline
       Running: rake assets:precompile
       rake aborted!
       undefined method `[]=' for nil:NilClass
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/config/initializers/database_connection.rb:7:in `block (2 levels) in <top (required)>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:28:in `block in on_load'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:27:in `each'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:27:in `on_load'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/config/initializers/database_connection.rb:5:in `block in <top (required)>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:36:in `call'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:44:in `each'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application/finisher.rb:62:in `block in <module:Finisher>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:30:in `instance_exec'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:30:in `run'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:55:in `block in run_initializers'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/initializable.rb:54:in `run_initializers'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application.rb:215:in `initialize!'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/railtie/configurable.rb:30:in `method_missing'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/config/environment.rb:5:in `<top (required)>'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:229:in `require'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:229:in `block in require'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:214:in `load_dependency'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:229:in `require'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application.rb:189:in `require_environment!'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/railties-4.0.2/lib/rails/application.rb:250:in `block in run_tasks_blocks'
       /tmp/build_2826537d-5a5c-43f7-b792-45112618d3df/vendor/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.1/lib/sprockets/rails/task.rb:54:in `block (2 levels) in define'
       Tasks: TOP => environment
       (See full trace by running task with --trace)
 !
 !     Precompiling assets failed.
 !

 !     Push rejected, failed to compile Ruby app

staging.rb

Glowcon::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 thread 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 Rails's static asset server (Apache or nginx will already do this).
  config.serve_static_assets = false

  # Compress JavaScripts and CSS.
  config.assets.compress = true
  config.assets.js_compressor = :uglifier
  config.assets.css_compressor = :yui

  # Do not fallback to assets pipeline if a precompiled asset is missed.
  config.assets.compile = false

  # Generate digests for assets URLs.
  config.assets.digest = true

  # Version of your assets, change this if you want to expire all your assets.
  config.assets.version = '1.0'

  # 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

  # Set to :debug to see everything in the log.
  config.log_level = :info

  # Mailer settings


  # 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"

  # Precompile additional assets.
  # application.js, application.scss, and all non-JS/CSS in app/assets folder are already added.
  # config.assets.precompile += %w( search.js )

  # 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 can not be found).
  config.i18n.fallbacks = true

  # Send deprecation notices to registered listeners.
  config.active_support.deprecation = :notify

  # Disable automatic flushing of the log to improve performance.
  # config.autoflush_log = false

  # Use default logging formatter so that PID and timestamp are not suppressed.
  config.log_formatter = ::Logger::Formatter.new
end