Heroku on Ubuntu 14.04 - ruby-on-rails

Question

I am currently following 'Ruby on Rails Tutorial' by Michael Hartl. On Chapter 3 when I try to deploy the working sample app with Heroku it is rejected, and even though I fully understand the error message I do not know how to correct it. Here is my Gemfile:
source 'https://rubygems.org'
ruby '2.0.0'
#ruby-gemset=railstutorial_rails_4_0
gem 'rails', '4.0.5'
group :development, :test do
gem 'sqlite3', '1.3.8'
gem 'rspec-rails', '2.13.1'
end
group :test do
gem 'selenium-webdriver', '2.35.1'
gem 'capybara', '2.1.0'
end
gem 'sass-rails', '4.0.1'
gem 'uglifier', '2.1.1'
gem 'coffee-rails', '4.0.1'
gem 'jquery-rails', '3.0.4'
gem 'turbolinks', '1.1.1'
gem 'jbuilder', '1.0.2'
group :doc do
gem 'sdoc', '0.3.20', require: false
end
group :production do
gem 'pg', '0.15.1'
gem 'rails_12factor', '0.0.2'
end
And here is the file where the issue originates which is config/environments/development.rb:
SampleApp::Application.configure do
# Settings specified here will take precedence over those in config/application.rb.
# In the development environment your application's code is reloaded on
# every request. This slows down response time but is perfect for development
# since you don't have to restart the web server when you make code changes.
config.cache_classes = false
# Do not eager load code on boot.
config.eager_load = false
# Show full error reports and disable caching.
config.consider_all_requests_local = true
config.action_controller.perform_caching = false
# Don't care if the mailer can't send.
config.action_mailer.raise_delivery_errors = false
# Print deprecation notices to the Rails logger.
config.active_support.deprecation = :log
# Raise an error on page load if there are pending migrations.
config.active_record.migration_error = :page_load
# Debug mode disables concatenation and preprocessing of assets.
# This option may cause significant delays in view rendering with a large
# number of complex assets.
config.assets.debug = true
# Adds additional error checking when serving assets at runtime.
# Checks for improperly declared sprockets dependencies.
# Raises helpful error messages.
config.assets.raise_runtime_errors = true
# Raises error for missing translations
# config.action_view.raise_on_missing_translations = true
end
The errors I get are attempting 'git push heroku master':
Running: rake assets:precompile
rake aborted!
NoMethodError: undefined method `configure' for #<SampleApp::Application:0x007fc7f03f7298>
and after a long list of paths I get:
!
! Precompiling assets failed.
!
! Push rejected, failed to compile Ruby app
To git#heroku.com:some-name.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git#heroku.com:some-name.git'
Any idea how to fix this please? I really would like to get deployments working under Ubuntu.
Thank you!

Answer 1

By default Rails 4 will not serve your assets. To enable this functionality you need to go into config/application.rb and add this line:
config.serve_static_assets = true
Have a read through this documentation on heroku as well - https://devcenter.heroku.com/articles/rails-4-asset-pipeline
Hope it helps. :)

Answer 2

Rails 4
The problem is a common issue with the Hartl tutorial - it derives from using Rails 3 in the tutorial, and a later version being used widely now
I tried looking for references on this, but I couldn't. I've found them somewhere before - will have another look for you.
Anyway, in Rails 4, need this (we have this in our Rails 4 apps):
#config/environments/development.rb
Rails.application.configure do
This sets the configure code block for the correct object. I think Rails changed some of its core functionality in 4.0+, which is why you're getting the issue now